Histologic Remission in Inflammatory Bowel Disease and Female Fertility: A Nationwide Study

BACKGROUND & AIMS

Inflammatory bowel disease (IBD) is linked to reduced female fertility, but it is unclear how fertility rates vary by histologic disease activity.

METHODS

Nationwide IBD cohort of Swedish women aged 15 to 44 years. We examined fertility rates during periods with vs without histologic inflammation (n = 21,046; follow-up, 1990-2016) and during periods with vs without clinical activity (IBD-related hospitalization, surgery, or treatment escalation) (n = 24,995; follow-up, 2006-2020). Accounting for sociodemographics and comorbidities, we used Poisson regression to estimate adjusted fertility rate ratios (aFRRs) for live births conceived during 12-month periods of histologic inflammation (vs histologic remission) and 3-month periods of clinically active IBD (vs quiescent IBD).

RESULTS

During periods with vs without histologic inflammation, there were 6.35 (95% confidence interval [CI], 5.98-6.73) and 7.09 (95% CI, 6.48-7.70) live births conceived per 100 person-years of follow-up, respectively, or 1 fewer child per 14 women with 10 years of histologic inflammation (aFRR, 0.90; 95% CI, 0.81-1.00). In women with histologic inflammation, fertility was similarly reduced in ulcerative colitis (UC) (aFRR, 0.89 [95% CI, 0.78-1.02]) and Crohn's disease (CD) (aFRR, 0.86 [95% CI, 0.72-1.04]). Clinical IBD activity was associated with an aFRR of 0.76 (95% CI, 0.72-0.79) or 1 fewer child per 6 women with 10 years of clinical activity. Fertility was reduced in clinically active UC (aFRR, 0.75 [95% CI, 0.70-0.81]) and CD (aFRR, 0.76 [95% CI, 0.70-0.82]). Finally, among women with clinically quiescent IBD, histologic inflammation (vs histologic remission) was associated with reduced fertility (aFRR, 0.85 [95% CI, 0.73-0.98]).

CONCLUSIONS

An association between histologic and clinical activity and reduced female fertility in CD and UC was found. Notably, histologic inflammation was also linked to reduced fertility in women with clinically quiescent IBD.

Duration of the active first stage of labour and severe perineal lacerations and maternal postpartum complications: a population-based cohort study

OBJECTIVE

The impact of first stage labour duration on maternal outcomes is sparsely investigated. We aimed to study the association between a longer active first stage and maternal complications in the early postpartum period.

DESIGN

A population-based cohort study.

SETTING

Regions of Stockholm and Gotland, Sweden, 2008-2020.

POPULATION

A cohort of 159 459 term, singleton, vertex pregnancies, stratified by parity groups.

METHODS

The exposure was active first stage duration, categorised in percentiles. Poisson regression analysis was performed to estimate the adjusted relative risk (aRR) and the 95% confidence interval (95% CI). To investigate the effect of second stage duration on the outcome, mediation analysis was performed.

MAIN OUTCOME MEASURES

Severe perineal lacerations (third or fourth degree), postpartum infection, urinary retention and haematoma in the birth canal or ruptured sutures.

RESULTS

The risks of severe perineal laceration, postpartum infection and urinary retention increased with a longer active first stage, both overall and stratified by parity group. The aRR increased with a longer active first stage, using duration of <50th percentile as the reference. In the ≥90th percentile category, the aRR for postpartum infection was 1.64 (95% CI 1.46-1.84) in primiparous women, 2.43 (95% CI 1.98-2.98) in parous women with no previous caesarean delivery (CD) and 2.33 (95% CI 1.65-3.28) in parous women with a previous CD. The proportion mediated by second stage duration was 33.4% to 36.9% for the different outcomes in primiparous women. The risk of haematoma or ruptured sutures did not increased with a longer active first stage.

CONCLUSIONS

Increasing active first stage duration is associated with maternal complications in the early postpartum period.

Safety of low weight gain or weight loss in pregnancies with class 1, 2, and 3 obesity: a population-based cohort study

BACKGROUND

There are concerns that current gestational weight gain recommendations for women with obesity are too high and that guidelines should differ on the basis of severity of obesity. In this study we investigated the safety of gestational weight gain below current recommendations or weight loss in pregnancies with obesity, and evaluated whether separate guidelines are needed for different obesity classes.

METHODS

In this population-based cohort study, we used electronic medical records from the Stockholm-Gotland Perinatal Cohort study to identify pregnancies with obesity (early pregnancy BMI before 14 weeks' gestation ≥30 kg/m2) among singleton pregnancies that delivered between Jan 1, 2008, and Dec 31, 2015. The pregnancy records were linked with Swedish national health-care register data up to Dec 31, 2019. Gestational weight gain was calculated as the last measured weight before or at delivery minus early pregnancy weight (at <14 weeks' gestation), and standardised for gestational age into z-scores. We used Poisson regression to assess the association of gestational weight gain z-score with a composite outcome of: stillbirth, infant death, large for gestational age and small for gestational age at birth, preterm birth, unplanned caesarean delivery, gestational diabetes, pre-eclampsia, excess postpartum weight retention, and new-onset longer-term maternal cardiometabolic disease after pregnancy, weighted to account for event severity. We calculated rate ratios (RRs) for our composite adverse outcome along the weight gain z-score continuum, compared with a reference of the current lower limit for gestational weight gain recommended by the US Institute of Medicine (IOM; 5 kg at term). RRs were adjusted for confounding factors (maternal age, height, parity, early pregnancy BMI, early pregnancy smoking status, prepregnancy cardiovascular disease or diabetes, education, cohabitation status, and Nordic country of birth).

FINDINGS

Our cohort comprised 15 760 pregnancies with obesity, followed up for a median of 7·9 years (IQR 5·8-9·4). 11 667 (74·0%) pregnancies had class 1 obesity, 3160 (20·1%) had class 2 obesity, and 933 (5·9%) had class 3 obesity. Among these pregnancies, 1623 (13·9%), 786 (24·9%), and 310 (33·2%), respectively, had weight gain during pregnancy below the lower limit of the IOM recommendation (5 kg). In pregnancies with class 1 or 2 obesity, gestational weight gain values below the lower limit of the IOM recommendation or weight loss did not increase risk of the adverse composite outcome (eg, at weight gain z-score -2·4, corresponding to 0 kg at 40 weeks: adjusted RR 0·97 [95% CI 0·89-1·06] in obesity class 1 and 0·96 [0·86-1·08] in obesity class 2). In pregnancies with class 3 obesity, weight gain values below the IOM limit or weight loss were associated with reduced risk of the adverse composite outcome (eg, adjusted RR 0·81 [0·71-0·89] at weight gain z-score -2·4, or 0 kg).

INTERPRETATION

Our findings support calls to lower or remove the lower limit of current IOM recommendations for pregnant women with obesity, and suggest that separate guidelines for class 3 obesity might be warranted.

FUNDING

Karolinska Institutet and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Acetaminophen Use During Pregnancy and Children's Risk of Autism, ADHD, and Intellectual Disability

Importance

Several studies suggest that acetaminophen (paracetamol) use during pregnancy may increase risk of neurodevelopmental disorders in children. If true, this would have substantial implications for management of pain and fever during pregnancy.

Objective

To examine the associations of acetaminophen use during pregnancy with children's risk of autism, attention-deficit/hyperactivity disorder (ADHD), and intellectual disability.

Design, Setting, and Participants

This nationwide cohort study with sibling control analysis included a population-based sample of 2 480 797 children born in 1995 to 2019 in Sweden, with follow-up through December 31, 2021.

Exposure

Use of acetaminophen during pregnancy prospectively recorded from antenatal and prescription records.

Main Outcomes and Measures

Autism, ADHD, and intellectual disability based on International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision codes in health registers.

Results

In total, 185 909 children (7.49%) were exposed to acetaminophen during pregnancy. Crude absolute risks at 10 years of age for those not exposed vs those exposed to acetaminophen were 1.33% vs 1.53% for autism, 2.46% vs 2.87% for ADHD, and 0.70% vs 0.82% for intellectual disability. In models without sibling control, ever-use vs no use of acetaminophen during pregnancy was associated with marginally increased risk of autism (hazard ratio [HR], 1.05 [95% CI, 1.02-1.08]; risk difference [RD] at 10 years of age, 0.09% [95% CI, -0.01% to 0.20%]), ADHD (HR, 1.07 [95% CI, 1.05-1.10]; RD, 0.21% [95% CI, 0.08%-0.34%]), and intellectual disability (HR, 1.05 [95% CI, 1.00-1.10]; RD, 0.04% [95% CI, -0.04% to 0.12%]). To address unobserved confounding, matched full sibling pairs were also analyzed. Sibling control analyses found no evidence that acetaminophen use during pregnancy was associated with autism (HR, 0.98 [95% CI, 0.93-1.04]; RD, 0.02% [95% CI, -0.14% to 0.18%]), ADHD (HR, 0.98 [95% CI, 0.94-1.02]; RD, -0.02% [95% CI, -0.21% to 0.15%]), or intellectual disability (HR, 1.01 [95% CI, 0.92-1.10]; RD, 0% [95% CI, -0.10% to 0.13%]). Similarly, there was no evidence of a dose-response pattern in sibling control analyses. For example, for autism, compared with no use of acetaminophen, persons with low (<25th percentile), medium (25th-75th percentile), and high (>75th percentile) mean daily acetaminophen use had HRs of 0.85, 0.96, and 0.88, respectively.

Conclusions and Relevance

Acetaminophen use during pregnancy was not associated with children's risk of autism, ADHD, or intellectual disability in sibling control analysis. This suggests that associations observed in other models may have been attributable to familial confounding.

Severe Perineal Lacerations in First Delivery: Association with Subsequent Reproductive Outcomes

Background: Severe perineal lacerations (SPLs), common worldwide, are associated with short- and long-term complications: pelvic floor disorders, fecal incontinence, fistula, and profound psychological impacts. Limited research suggests that experiencing SPL may influence future reproductive intentions, but research on outcomes is lacking. Methods: We analyzed the effect of experiencing SPL during a first delivery among a large cohort of Swedish births between 1992 and 2013. We used linear and multinomial logistic regression to estimate the associations between SPL and four reproductive outcomes: subsequent total birth number, probability of a second birth, interpregnancy interval (IPI), and subsequent scheduled cesarean birth. Results: Among 947,035 singleton live-born first-births, we found that experiencing SPL was associated with slightly fewer overall births in fully adjusted models (a decrease of -0.020 births; 95% confidence interval [CI]: -0.028 to -0.012), but no difference in the probability of a second birth (risk ratio [RR]: 1.00; 95% CI: 0.99 to 1.00) or IPI. Scheduled cesarean was increased in births after SPL (adjusted RR: 4.57; 95% CI: 4.42 to 4.73). A secondary comparison of SPL to severe postpartum hemorrhage suggests that some of these observed differences may be related to experiencing any severe outcome, and some specifically to perineum disruption. Conclusion: This study provides a deeper understanding of the long-term impacts of SPL, which may be useful in informing best clinical practices for supporting women who have experienced SPL.

Neonatal Outcomes After COVID-19 Vaccination in Pregnancy

Importance

Better knowledge about neonatal adverse events after COVID-19 vaccination during pregnancy could help address concerns about vaccine safety.

Objective

To evaluate the risks of neonatal adverse events after exposure to COVID-19 vaccination during pregnancy.

Design, Setting, and Participants

Population-based cohort study including all infants in Sweden and Norway born from June 2021 to January 2023. Unique personal identity numbers were used to link individual information from different national registers.

Exposure

Administration of any mRNA vaccine against COVID-19 during pregnancy, irrespective of previous vaccination, number of doses during pregnancy, or vaccine manufacturer.

Main Outcomes and Measures

Outcomes were neonatal conditions with bleeding/thrombosis or inflammation/infection; disorders of the central nervous system; circulatory, respiratory, or gastrointestinal problems; and neonatal mortality. Statistical methods included logistic regression adjusted for characteristics of the pregnant individuals, with additional restricted and stratified analyses.

Results

Of 196 470 newborn infants included (51.3% male, 93.8% born at term, 62.5% born in Sweden), 94 303 (48.0%) were exposed to COVID-19 vaccination during pregnancy. Exposed infants exhibited no increased odds of adverse neonatal outcomes, and they exhibited lower odds for neonatal nontraumatic intracranial hemorrhage (event rate, 1.7 vs 3.2/1000; adjusted odds ratio [aOR], 0.78 [95% CI, 0.61-0.99]), hypoxic-ischemic encephalopathy (1.8 vs 2.7/1000; aOR, 0.73 [95% CI, 0.55-0.96]), and neonatal mortality (0.9 vs 1.8/1000; aOR, 0.68 [95% CI, 0.50-0.91]). Subgroup analyses found a similar association between vaccination during pregnancy and lower neonatal mortality; subgroups were restricted to infants delivered by individuals unvaccinated before pregnancy, individuals vaccinated before pregnancy, individuals vaccinated after a general recommendation of vaccination during pregnancy was issued, and individuals without COVID-19 infection during pregnancy. Analyses restricted to term infants, singleton births, or infants without birth defects yielded similar results. Stratifying the analysis by vaccine manufacturer did not attenuate the association between vaccination and low neonatal mortality.

Conclusions and Relevance

In this large population-based study, vaccination of pregnant individuals with mRNA COVID-19 vaccines was not associated with increased risks of neonatal adverse events in their infants.

Neurological development in children born moderately or late preterm: national cohort study

OBJECTIVE

To assess long term neurodevelopmental outcomes of children born at different gestational ages, particularly 32-33 weeks (moderately preterm) and 34-36 weeks (late preterm), compared with 39-40 weeks (full term).

DESIGN

Nationwide cohort study.

SETTING

Sweden.

PARTICIPANTS

1 281 690 liveborn singleton children without congenital malformations born at 32+0 to 41+6 weeks between 1998 and 2012.

MAIN OUTCOME MEASURES

The primary outcomes of interest were motor, cognitive, epileptic, hearing, and visual impairments and a composite of any neurodevelopmental impairment, diagnosed up to age 16 years. Hazard ratios and 95% confidence intervals were estimated using Cox regression adjusted for parental and infant characteristics in the study population and in the subset of full siblings. Risk differences were also estimated to assess the absolute risk of neurodevelopmental impairment.

RESULTS

During a median follow-up of 13.1 years (interquartile range 9.5-15.9 years), 75 311 (47.8 per 10 000 person years) liveborn singleton infants without congenital malformations had at least one diagnosis of any neurodevelopmental impairment: 5899 (3.6 per 10 000 person years) had motor impairment, 27 371 (17.0 per 10 000 person years) cognitive impairment, 11 870 (7.3 per 10 000 person years) epileptic impairment, 19 700 (12.2 per 10 000 person years) visual impairment, and 20 393 (12.6 per 10 000 person years) hearing impairment. Children born moderately or late preterm, compared with those born full term, showed higher risks for any impairment (hazard ratio 1.73 (95% confidence interval 1.60 to 1.87) and 1.30 (1.26 to 1.35); risk difference 4.75% (95% confidence interval 3.88% to 5.60%) and 2.03% (1.75% to 2.35%), respectively) as well as motor, cognitive, epileptic, visual, and hearing impairments. Risks for neurodevelopmental impairments appeared highest from 32 weeks (the earliest gestational age), gradually declined until 41 weeks, and were also higher at 37-38 weeks (early term) compared with 39-40 weeks. In the sibling comparison analysis (n=349 108), most associations remained stable except for gestational age and epileptic and hearing impairments, where no association was observed; for children born early term the risk was only higher for cognitive impairment compared with those born full term.

CONCLUSIONS

The findings of this study suggest that children born moderately or late preterm have higher risks of adverse neurodevelopmental outcomes. The risks should not be underestimated as these children comprise the largest proportion of children born preterm. The findings may help professionals and families achieve a better risk assessment and follow-up.

Maternal intrahepatic cholestasis of pregnancy and neurodevelopmental conditions in offspring: A population-based cohort study of 2 million Swedish children

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) is the most common obstetric liver disorder and is associated with an increased risk of iatrogenic preterm birth and adverse infant outcomes. Hence, there are several plausible pathways through which ICP could affect offspring neurodevelopment. However, to the best of our knowledge, no studies have investigated these associations. Thus, we aimed to determine whether ICP is associated with offspring neurodevelopmental conditions.

METHODS AND FINDINGS

In this Swedish register-based cohort study, we included singleton non-adopted children born in Sweden between the 1st of January 1987 and the 31st of December 2010, who were resident in Sweden >5 years, with no missing covariate information, which we followed until the 31st of December 2016. Maternal ICP diagnosis and the date of the initial diagnosis during pregnancy were obtained from the National Patient Register. Offspring diagnoses of attention deficit/hyperactivity disorder (ADHD), autism, or intellectual disability were obtained from the National Patient Register, and the dispensation of ADHD medications were obtained from the Prescribed Drug Register. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression while controlling for observed confounders and unobserved confounders shared among full siblings and maternal full cousins. A total of 2,375,856 children were included in the study; 81.6% of them were of Nordic origin, and 51.4% were male. Of these, 10,378 (0.44%) were exposed to ICP. During a median of 18 years follow-up (interquartile range 11 to 24), 143,746 (6.05%) of children were diagnosed with a neurodevelopmental condition. After adjusting for child's sex, birth year, birth month, maternal age, highest parental education level, maternal birth country, birth order, maternal psychiatric history, ICP was associated with increased odds of offspring neurodevelopmental conditions (OR 1.22, 95% CI 1.13 to 1.31), particularly among those exposed to early-onset ICP (OR 2.38, 95% CI 1.71 to 3.30) as compared to ICP diagnosed after reaching term (≥37 weeks of gestation) (OR 1.08, 95% CI 0.97 to 1.20). The findings of early-onset ICP were consistent in family-based analyses. Within-family comparisons of full maternal cousins yielded an OR of 2.99 (95% CI 1.48 to 6.04), and comparisons of full siblings showed an OR of 1.92 (95% CI 0.92 to 4.02), though the latter was less precise. The findings were consistent across specific neurodevelopmental conditions and different analytical approaches. The primary limitations of this study included its observational design, the absence of data on ICP therapeutics, and the lack of bile acid measures.

CONCLUSIONS

In this study, we observed that exposure to ICP during gestation is associated with an increased likelihood of neurodevelopmental conditions in offspring, particularly in cases of early-onset ICP. Further studies are warranted to better understand the role of early-ICP in offspring neurodevelopment.

One-year survival and outcomes of infants born at 22 and 23 weeks of gestation in Sweden 2004-2007, 2014-2016 and 2017-2019

OBJECTIVE

To explore associations between perinatal activity and survival in infants born at 22 and 23 weeks of gestation in Sweden.

DESIGN/SETTING

Data on all births at 22 and 23 weeks' gestational age (GA) were prospectively collected in 2004-2007 (T1) or obtained from national registers in 2014-2016 (T2) and 2017-2019 (T3). Infants were assigned perinatal activity scores based on 3 key obstetric and 4 neonatal interventions.

MAIN OUTCOME

One-year survival and survival without major neonatal morbidities (MNM): intraventricular haemorrhage grade 3-4, cystic periventricular leucomalacia, surgical necrotising enterocolitis, retinopathy of prematurity stage 3-5 or severe bronchopulmonary dysplasia. The association of GA-specific perinatal activity score and 1-year survival was also determined.

RESULTS

977 infants (567 live births and 410 stillbirths) were included: 323 born in T1, 347 in T2 and 307 in T3. Among live-born infants, survival at 22 weeks was 5/49 (10%) in T1 and rose significantly to 29/74 (39%) in T2 and 31/80 (39%) in T3. Survival was not significantly different between epochs at 23 weeks (53%, 61% and 67%). Among survivors, the proportions without MNM in T1, T2 and T3 were 20%, 17% and 19% for 22 weeks and 17%, 25% and 25% for 23 weeks' infants (p>0.05 for all comparisons). Each 5-point increment in GA-specific perinatal activity score increased the odds for survival in first 12 hours of life (adjusted OR (aOR) 1.4; 95% CI 1.3 to 1.6) in addition to 1-year survival (aOR 1.2; 95% CI 1.1 to 1.3), and among live-born infants it was associated with increased survival without MNM (aOR 1.3; 95% CI 1.1 to 1.4).

CONCLUSION

Increased perinatal activity was associated with reduced mortality and increased chances of survival without MNM in infants born at 22 and 23 weeks of GA.

Maternal and pregnancy predictive risk factors for having a compensated maternal injury claim: a Swedish nationwide cohort study

To describe trends and identify maternal and pregnancy predictive risk factors for having a compensated claim for a maternal injury during delivery, as a proxy for having received suboptimal care. This nationwide retrospective cohort study included 1 754 869 births in Sweden between 2000 and 2016, including 4488 maternal injury claims filed with The National Swedish Patient Insurance Company (Löf), of which 1637 were compensated. Descriptive statistics on maternal and pregnancy characteristics, trends in filed/compensated claims over time, and distribution of compensated claims by clinical classification are presented. Characteristics associated with suboptimal care were identified using multivariable logistic regression, with mutual adjustment in the final model. Compensated claims were sorted into 14 clinical classifications (ICD-10 codes for main condition, injury, and causality). Overall, there was a two-fold increase in filed claims from 2000 to 2016, peaking in 2014. The rate of compensated claims only increased marginally, and 36.5% of filed claims were deemed avoidable. Perineal and pelvic floor injuries, as well as medical and diagnostic errors, were responsible for the majority of compensated claims. Women with a previous caesarean section, post term delivery, chronic or gestational disease, > 13 antenatal visits, or a multiple pregnancy had increased risk of having a compensated claim for a maternal injury during delivery. Understanding the risk factors for having a compensated maternal injury claim may guide health workers and maternity wards in improving the quality and organisation of care to reduce the risk of childbirth related injuries.

[Swedish Medical Birth Register 50 years - a source for scientific publications]

The nationwide Swedish Medical Birth Register (MBR) includes more than 98% of all births in Sweden since 1973. The MBR is updated annually, and is based on information from antenatal, obstetric, and neonatal records. Maternal information includes self-reported medical history, socio-demographic factors, smoking and snuff use, medication use, height and measured weight. Birth and neonatal/postpartal data include birth date, mode of delivery, singleton or multiple birth, gestational age, stillbirth, birth weight, birth length, head circumference, infant sex, Apgar scores, and maternal and infant diagnoses/procedures. The overall quality of the MBR is very high, partly due to the semi-automated data extraction from the standardized regional electronic health records. The MBR can be linked to other health registers through the unique personal identity numbers of mothers and live-born offspring. More than 1000 scientific publications have used MBR as a data source.

Pregnancy Outcomes in Females with Eosinophilic Esophagitis: A Nationwide Population-Based Study

Introduction

Eosinophilic esophagitis (EoE) is a chronic, allergic inflammatory disease of the esophagus. It has a peak incidence in the 2nd and 3rd decades of life. Despite this, little is known about pregnancy outcomes in patients with EoE.

Methods

Using a validated histopathologic and nationwide population-based cohort for the diagnosis of EoE, we examined maternal and fetal outcomes, with preterm birth as the primary outcome, in females with EoE compared to matched controls. Odds ratios (ORs) were calculated using logistic regression.

Results

Between 1992 and 2016, we identified 19 females with EoE who gave birth to 23 children (reference births: n = 115). There was 1 (4.3%) preterm birth in the EoE cohort versus 8 (7.0%) in the reference cohort (OR = 0.60; 95% CI = 0.07-5.14). Secondary fetal outcomes included stillbirth, neonatal death, small for gestational age, low birth weight (LBW), and low Apgar score. Of these, LBW (<2,500 g) in patients with EoE compared to controls correlated to an OR of 12.42 (95% CI = 1.26-122.42); however, this finding was based on very low numbers. The remaining fetal outcomes were not significantly different between females with EoE and controls. Secondary pregnancy and maternal outcomes including induction of labor, instrumental delivery, gestational diabetes, or pre-eclampsia were not significantly different between patients with EoE and controls.

Discussion/Conclusion

Overall in this nationwide cohort study, we did not find increased association of preterm birth in patients with EoE.

Pregnancy Weight Gain After Gastric Bypass or Sleeve Gastrectomy

Importance

Pregnancy weight gain may affect the association of bariatric surgery with postsurgery pregnancy outcomes. However, the association of pregnancy weight gain with bariatric surgery is unclear.

Objective

To compare pregnancy weight gain among women with a history of bariatric surgery vs those without and to investigate whether pregnancy weight gain differs by surgical procedure, surgery-to-conception interval, and/or surgery-to-conception weight loss.

Design, Setting, and Participants

This nationwide, population-based matched cohort study was conducted in Sweden from 2014 to 2021. Singleton pregnancies with a history of bariatric surgery were propensity score matched (1:1) to pregnancies without such a history according to early-pregnancy body mass index (BMI), prepregnancy diabetes, prepregnancy hypertension, maternal age, smoking status, education level, height, country of birth, and delivery year. In addition, post-gastric bypass pregnancies were matched to post-sleeve gastrectomy pregnancies using the same matching strategy. Data analysis was performed from November 2022 to May 2023.

Exposure

History of bariatric surgery.

Main Outcomes and Measures

Pregnancy weight gain was standardized by gestational age into early-pregnancy BMI-specific z scores.

Results

This study included 12 776 pregnancies, of which 6388 had a history of bariatric surgery and 6388 were matched controls. The mean (SD) age was 31.6 (4.9) years for the surgery group and 31.4 (5.2) for the matched controls, with an early-pregnancy mean (SD) BMI of 29.4 (5.2) in both groups. Across all early-pregnancy BMI strata, women with a history of bariatric surgery had lower pregnancy weight gain than matched controls. The differences in pregnancy weight gain z score values between the 2 groups were -0.33 (95% CI, -0.43 to -0.23) for normal weight, -0.33 (95% CI, -0.40 to -0.27) for overweight, -0.21 (95% CI, -0.29 to -0.13) for obese class I, -0.16 (95% CI, -0.29 to -0.03) for obese class II, and -0.08 (95% CI, -0.28 to 0.13) for obese class III. Pregnancy weight gain did not differ by surgical procedure. A shorter surgery-to-conception interval (particularly within 1 year) or lower surgery-to-conception weight loss was associated with lower pregnancy weight gain.

Conclusions and Relevance

In this nationwide matched cohort study, women with a history of bariatric surgery had lower pregnancy weight gain than matched controls with similar early-pregnancy characteristics. Pregnancy weight gain was lower in those with a shorter surgery-to-conception interval or lower surgery-to-conception weight loss, but did not differ by surgical procedure.

Pregnancy-Induced Hypertensive Disorder and Risks of Future Ischemic and Nonischemic Heart Failure

BACKGROUND

Although adverse pregnancy outcomes are associated with an increased risk of cardiovascular disease, studies on timing and subtypes of heart failure after a hypertensive pregnancy are lacking.

OBJECTIVES

The goal of this study was to assess the association between pregnancy-induced hypertensive disorder and risk of heart failure, according to ischemic and nonischemic subtypes, and the impact of disease characteristics and the timing of heart failure risks.

METHODS

This was a population-based matched cohort study, comprising all primiparous women without a history of cardiovascular disease included in the Swedish Medical Birth Register between 1988 and 2019. Women with pregnancy-induced hypertensive disorder were matched with women with normotensive pregnancies. Through linkage with health care registers, all women were followed up for incident heart failure, classified as ischemic or nonischemic.

RESULTS

In total, 79,334 women with pregnancy-induced hypertensive disorder were matched with 396,531 women with normotensive pregnancies. During a median follow-up of 13 years, rates of all heart failure subtypes were more common among women with pregnancy-induced hypertensive disorder. Compared with women with normotensive pregnancies, adjusted HRs (aHRs) with 95% CIs were as follows: heart failure overall, aHR: 1.70 (95% CI: 1.51-1.91); ischemic heart failure, aHR: 2.28 (95% CI: 1.74-2.98); and nonischemic heart failure, aHR: 1.60 (95% CI: 1.40-1.83). Disease characteristics indicating severe hypertensive disorder were associated with higher heart failure rates, and rates were highest within the first years after the hypertensive pregnancy but remained significantly increased thereafter.

CONCLUSIONS

Pregnancy-induced hypertensive disorder is associated with an increased short-term and long-term risk of incident ischemic and nonischemic heart failure. Disease characteristics indicating more severe forms of pregnancy-induced hypertensive disorder amplify the heart failure risks.

First stage of labour duration and associated risk of adverse neonatal outcomes

Prior evidence evaluating the benefits and harms of expectant labour duration during active first stage is inconclusive regarding potential consequences for the neonate. Population-based cohort study in Stockholm-Gotland region, Sweden, including 46,040 women (Robson 1), between October 1st, 2008 and June 15th, 2020. Modified Poisson regression was used for the association between active first stage of labour duration and adverse neonatal outcomes. 94.2% experienced a delivery with normal neonatal outcomes. Absolute risk for severe outcomes increased from 1.9 to 3.0%, moderate outcomes increased from 2.8 to 6.2% (> 10.1 h). Compared to the reference, (< 5.1 h; median), the adjusted relative risk (aRR) of severe neonatal outcome significantly increased beyond 10.1 h (> 90th percentile) (aRR 1.53, 95% CI 1.26, 1.87), for moderate neonatal outcome the aRR began to slowly increase beyond 5.1 h (≥ 50 percentile; aRR 1.40, 95% CI 1.24, 1.58). Mediation analysis indicate that most of the association was due to a longer active first stage of labour, 13% (severe neonatal outcomes) and 20% (moderate neonatal outcomes) of the risk was mediated (indirect effect) by longer second stage of labour duration. We report an association between increasing active first stage duration and increased risk of adverse neonatal outcomes. We did not observe a clear labour duration risk threshold.

No Increased Risk of Cardiac Birth Defects in Infants of Mothers With Celiac Disease: A Population and Sibling Comparison

INTRODUCTION

Several earlier studies have indicated an increased risk of cardiac birth defects among infants born to mothers with celiac disease (CeD). Through linking nationwide Swedish health care registries, we aimed to investigate maternal CeD and risk of any or cardiac birth defects in their offspring.

METHODS

We performed a retrospective cohort study of infants born between 2002 and 2016 to women with biopsy-proven CeD (villous atrophy, Marsh III) matched to infants born to nonceliac women from the general population. Conditional logistic regression with odds ratios (OR) and their 95% confidence intervals (CI) was used to determine the association between maternal CeD and birth defects. To minimize the impact of intrafamilial confounding, we also compared infants born to mothers with CeD with infants born to their nonaffected sisters.

RESULTS

A total of 6,990 infants were born to mothers with diagnosed CeD compared with 34,643 infants born to reference mothers. Any birth defect was seen in 234 (33 per 1,000 infants) and 1,244 (36/1,000) reference infants corresponding to an OR of 0.93 (95% CI 0.81-1.08). Cardiac birth defects were seen in 113 (16/1,000) vs 569 (16/1,000) infants (OR 0.98, 95% CI 0.80-1.20). Similar OR for any and cardiac birth defects were also seen in sibling comparisons.

DISCUSSION

We found no statistically significant risk of any or cardiac birth defects in infants born to mothers with diagnosed CeD compared with the general population and to their nonaffected sisters.

Maternal, pregnancy and neonatal outcomes in triplet pregnancies in Sweden - a nationwide cohort study

Background

Triplet pregnancies carry a high risk of pregnancy-related complications. The primary aim of this study was to describe maternal, pregnancy, and neonatal outcomes in expectantly managed triplet pregnancies in Sweden. The secondary aim was to compare outcomes in expectantly managed triplet pregnancies with triplet pregnancies where fetal reduction had been performed with the only indication to reduce the number of fetuses.

Methods

Nationwide cohort study based on linkage of data from three national Swedish registers. Triplet pregnancies with delivery at gestational age ≥ 22+0 weeks between 2014 and 2019 were included.

Results

In the main cohort of expectantly managed triplet pregnancies (n = 106), 98% (312/318) of infants were liveborn with a mean gestational age at birth of 32+3 weeks and a mean birthweight of 1,726 g. Nine percent (n = 29) suffered from severe neonatal morbidity, and 4% (n = 12) died during the neonatal period. In the reduced cohort (n = 13 pregnancies), all infants were liveborn (n = 22). Mean gestational age at birth (36+0 weeks) and mean birthweight (2,444 g) were higher than in the expectantly managed cohort (P < 0.01 for both comparisons). There were no cases of severe neonatal morbidity (P = 0.24) or mortality (P = 1.00).

Conclusion

Overall neonatal survival from 22+0 weeks of gestation in expectantly managed triplet pregnancies in Sweden was high. Nine out of 10 infants did not suffer from severe neonatal morbidity. Fetal reduction was performed in only a very small number of cases and was associated with higher gestational age at birth and higher birth weight.

Maternal and fetal outcomes in acute hepatic porphyria: A Swedish National Cohort Study

Current knowledge of pregnancy and perinatal outcomes in women with acute hepatic porphyria (AHP) is largely based on biochemical disease models, case reports, and case series. We performed a nationwide, registered-based cohort study to investigate the association between maternal AHP and the risk of adverse pregnancy and perinatal outcomes. All women in the Swedish Porphyria Register with confirmed AHP aged 18 years or older between 1987 and 2015 and matched general population comparators, with at least one registered delivery in the Swedish Medical Birth Register were included. Risk ratios (RRs) of pregnancy complications, delivery mode and perinatal outcomes were estimated and adjusted for maternal age at delivery, area of residency, birth year and parity. Women with acute intermittent porphyria (AIP), the most common form of AHP, were further categorized according to maximal lifetime urinary porphobilinogen (U-PBG) levels. The study included 214 women with AHP and 2174 matched comparators. Women with AHP presented with a higher risk for pregnancy-induced hypertensive disorder (aRR 1.73, 95% CI 1.12-2.68), gestational diabetes (aRR 3.41, 95% CI 1.69-6.89), and small-for-gestational-age birth (aRR 2.08, 95% CI 1.26-3.45). In general, RRs were higher among women with AIP who had high lifetime U-PBG levels. Our study shows an increased risk for pregnancy induced hypertensive disease, gestational diabetes, and small for gestational age births for AHP women, with higher relative risks for women with biochemically active AIP. No increased risk for perinatal death or malformations was observed.

Pregnancy, Delivery, and Neonatal Outcomes Associated With Maternal Obsessive-Compulsive Disorder: Two Cohort Studies in Sweden and British Columbia, Canada

Importance

Obsessive-compulsive disorder (OCD) is associated with adverse health-related outcomes. However, pregnancy and neonatal outcomes among women with OCD have been sparsely studied.

Objective

To evaluate associations of maternal OCD with pregnancy, delivery, and neonatal outcomes.

Design, Setting, and Participants

Two register-based cohort studies in Sweden and British Columbia (BC), Canada, included all singleton births at 22 weeks or more of gestation between January 1, 1999 (Sweden), or April 1, 2000 (BC), and December 31, 2019. Statistical analyses were conducted between August 1, 2022, and February 14, 2023.

Exposure

Maternal OCD diagnosis recorded before childbirth and use of serotonin reuptake inhibitors (SRIs) during pregnancy.

Main Outcomes and Measures

Pregnancy and delivery outcomes examined were gestational diabetes, preeclampsia, maternal infection, antepartum hemorrhage or placental abruption, premature rupture of membranes, induction of labor, mode of delivery, and postpartum hemorrhage. Neonatal outcomes included perinatal death, preterm birth, small for gestational age, low birth weight (<2500 g), low 5-minute Apgar score, neonatal hypoglycemia, neonatal jaundice, neonatal respiratory distress, neonatal infections, and congenital malformations. Multivariable Poisson log-linear regressions estimated crude and adjusted risk ratios (aRRs). In the Swedish cohort, sister and cousin analyses were performed to account for familial confounding.

Results

In the Swedish cohort, 8312 pregnancies in women with OCD (mean [SD] age at delivery, 30.2 [5.1] years) were compared with 2 137 348 pregnancies in unexposed women (mean [SD] age at delivery, 30.2 [5.1] years). In the BC cohort, 2341 pregnancies in women with OCD (mean [SD] age at delivery, 31.0 [5.4] years) were compared with 821 759 pregnancies in unexposed women (mean [SD] age at delivery, 31.3 [5.5] years). In Sweden, maternal OCD was associated with increased risks of gestational diabetes (aRR, 1.40; 95% CI, 1.19-1.65) and elective cesarean delivery (aRR, 1.39; 95% CI, 1.30-1.49), as well as preeclampsia (aRR, 1.14; 95% CI, 1.01-1.29), induction of labor (aRR, 1.12; 95% CI, 1.06-1.18), emergency cesarean delivery (aRR, 1.16; 95% CI, 1.08-1.25), and postpartum hemorrhage (aRR, 1.13; 95% CI, 1.04-1.22). In BC, only emergency cesarean delivery (aRR, 1.15; 95% CI, 1.01-1.31) and antepartum hemorrhage or placental abruption (aRR, 1.48; 95% CI, 1.03-2.14) were associated with significantly higher risk. In both cohorts, offspring of women with OCD were at elevated risk of low Apgar score at 5 minutes (Sweden: aRR, 1.62; 95% CI, 1.42-1.85; BC: aRR, 2.30; 95% CI, 1.74-3.04), as well as preterm birth (Sweden: aRR, 1.33; 95% CI, 1.21-1.45; BC: aRR, 1.58; 95% CI, 1.32-1.87), low birth weight (Sweden: aRR, 1.28; 95% CI, 1.14-1.44; BC: aRR, 1.40; 95% CI, 1.07-1.82), and neonatal respiratory distress (Sweden: aRR, 1.63; 95% CI, 1.49-1.79; BC: aRR, 1.47; 95% CI, 1.20-1.80). Women with OCD taking SRIs during pregnancy had an overall increased risk of these outcomes, compared with those not taking SRIs. However, women with OCD not taking SRIs still had increased risks compared with women without OCD. Sister and cousin analyses showed that at least some of the associations were not influenced by familial confounding.

Conclusion and Relevance

These cohort studies suggest that maternal OCD was associated with an increased risk of adverse pregnancy, delivery, and neonatal outcomes. Improved collaboration between psychiatry and obstetric services and improved maternal and neonatal care for women with OCD and their children is warranted.

Association between SARS-CoV-2 infection and newly diagnosed hypertension during pregnancy: prospective, population based cohort study

Objective

To study the association between SARS-CoV-2 infection and newly diagnosed hypertension during pregnancy.

Design

Prospective, population based cohort study.

Setting

All singleton pregnancies after 22 completed gestational weeks registered in the Swedish Pregnancy Register and the Medical Birth Registry of Norway, from 1 March 2020 to 24 May 2022.

Participants

312 456 individuals available for analysis (201 770 in Sweden and 110 686 in Norway), with pregnancies that reached 42 completed gestational weeks by the end of follow-up in the pregnancy registries, excluding individuals with SARS-CoV-2 infection before pregnancy and those with a diagnosis of pre-existing hypertension or onset of hypertension before 20 gestational weeks.

Main outcome measures

Newly diagnosed hypertension during pregnancy was defined as a composite outcome of a diagnosis of gestational hypertension, pre-eclampsia, HELLP (haemolysis, elevated liver enzymes, low platelets) syndrome, or eclampsia, from gestational week 20 to one week after delivery. The association between SARS-CoV-2 infection and hypertension during pregnancy was investigated with a stratified Cox proportional hazard model, adjusting for maternal age, body mass index, parity, smoking, region of birth, education, income, coexisting medical conditions, previous hypertension during pregnancy, number of healthcare visits during the past year, and vaccination against SARS-CoV-2. Pre-eclampsia was also analysed as a separate outcome.

Results

Of 312 456 individuals available for analysis, 8% (n=24 566) had SARS-CoV-2 infection any time during pregnancy, 6% (n=18 051) had a diagnosis of hypertension during pregnancy, and 3% (9899) had pre-eclampsia. SARS-CoV-2 infection during pregnancy was not associated with an increased risk of hypertension during pregnancy (adjusted hazard ratio 0.99, 95% confidence interval 0.93 to 1.04) or pre-eclampsia (0.98, 0.87 to 1.10). The results were similar for SARS-CoV-2 infection in all gestational trimesters and in different time periods that corresponded to dominance of different variants of the SARS-CoV-2 virus.

Conclusions

This population based study did not find any evidence of an association between SARS-CoV-2 infection during pregnancy and an increased risk of hypertension during pregnancy or pre-eclampsia.

Pregnancy and neonatal outcomes among women with early-onset colorectal cancer: a nationwide case-control study

Background

Early-onset colorectal cancer has risen worldwide, leaving more women with colorectal cancer at reproductive ages. We aimed to investigate the risk of adverse pregnancy and neonatal outcomes among women with early-onset colorectal cancer.

Methods

We conducted a nationwide, matched case-control study of maternal/pregnancy outcomes including pre-eclampsia and Cesarean delivery (C-section) as well as neonatal outcomes including preterm birth among 207 births in women with early-onset colorectal cancer (ages 18-49) and 1019 births in women without colorectal cancer in Sweden (1992-2019). Early-onset colorectal cancer cases were identified through the Cancer Register, and outcome data were retrieved through linkage to Medical Birth Register and National Patient Register. Using conditional logistic regression, we estimated multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

Findings

Between Jan 1, 1992, and Dec 31, 2019, women with early-onset colorectal cancer who gave birth had increased odds of pre-eclampsia (7.2% vs 3.2%; OR = 2.52, 95%CI = 1.25-5.08), any C-section (24.6% vs 19.4%; OR = 1.43, 95%CI = 1.00-2.06), particularly emergency C-section (17.4% vs 10.5%; OR = 1.79, 95%CI = 1.17-2.75), after adjustment for maternal education level, country of birth, body mass index and smoking in early pregnancy, and comorbidities. Maternal history of early-onset colorectal cancer was also associated with offspring preterm birth (12.1% vs 5.2%; OR = 2.31, 95%CI = 1.34-3.99), delineated as spontaneous (OR = 1.06, 95%CI = 0.47-2.39) or medically-indicated preterm birth (OR = 4.48, 95%CI = 2.05-9.79). There was no increased risk of congenital malformation or small for gestational age birth.

Interpretation

In this population-based study, maternal history of early-onset colorectal cancer was associated with risk of both adverse pregnancy (pre-eclampsia, C-section) and neonatal outcomes (preterm birth).

Funding

US National Institutes of Health, Swedish Society of Medicine, Swedish Cancer Foundation.

Maternal suicide attempts and deaths in the first year after cesarean delivery

BACKGROUND

Cesarean delivery (CD) has been associated with postpartum psychiatric disorders, but less is known about the risk of suicidal behaviors. We estimated the incidence and risk of suicide attempts and deaths during the first postpartum year in mothers who delivered via CD v. vaginally.

METHOD

All deliveries in Sweden between 1973 and 2012 were identified. The mothers were followed since delivery for 12 months or until the date of one of the outcomes (i.e. suicide attempt or death by suicide), death by other causes or emigration. Associations were estimated using Cox proportional hazards regression models.

RESULTS

Of 4 016 789 identified deliveries, 514 113 (12.8%) were CDs and 3 502 676 (87.2%) were vaginal deliveries. During the 12-month follow-up, 504 (0.098%) suicide attempts were observed in the CD group and 2240 (0.064%) in the vaginal delivery group (risk difference: 0.034%), while 11 (0.0037%) deaths by suicide were registered in the CD group and 109 (0.0029%) in the vaginal delivery group (risk difference: 0.008%). Compared to vaginal delivery, CD was associated with an increased risk of suicide attempts [hazard ratio (HR) 1.46; 95% CI 1.32-1.60], but not of deaths by suicide (HR 1.44; 95% CI 0.88-2.36).

CONCLUSIONS

Maternal suicidal behaviors during the first postpartum year were uncommon in Sweden. Compared to vaginal delivery, CD was associated with a small increased risk of suicide attempts, but not death by suicide. Improved understanding of the association between CD and maternal suicidal behaviors may promote more appropriate measures to improve maternal mental well-being and further reduce suicidal risks.

Evaluation of Birth by Cesarean Delivery and Development of Early-Onset Colorectal Cancer

Importance

The incidence of early-onset colorectal cancer (CRC), diagnosed younger than 50 years of age, has increased worldwide. Gut dysbiosis throughout the life course is hypothesized as a leading mechanism, yet epidemiologic data are limited.

Objective

To prospectively examine the association between birth by cesarean delivery and early-onset CRC among offspring.

Design, Setting, and Participants

In this population-based, nationwide case-control study in Sweden, adults diagnosed with CRC between 18 and 49 years of age from 1991 to 2017 were identified through the Epidemiology Strengthened by Histopathology Reports in Sweden (ESPRESSO) cohort. Up to 5 general population control individuals without CRC were matched with each case on age, sex, calendar year, and county of residence. Pathology-confirmed end points were linked with the Swedish Medical Birth Register and other national registers. Analyses were conducted from March 2022 through March 2023.

Exposure

Birth by cesarean delivery.

Main Outcomes and Measures

The primary outcome was development of early-onset CRC in the overall population and by sex.

Results

We identified 564 case patients with incident early-onset CRC (mean [SD] age, 32.9 [6.2] years; 284 [50.4%] male) and 2180 matched controls (mean [SD] age, 32.7 [6.3] years; 1104 [50.6%] male). Compared with vaginal delivery, birth by cesarean delivery was not associated with early-onset CRC in the overall population (adjusted odds ratio [aOR], 1.28; 95% CI, 0.91-1.79) after multivariable adjustment for matching and maternal and pregnancy-related factors. A positive association was found for females (aOR, 1.62; 95% CI, 1.01-2.60), but there was no association for males (aOR, 1.05; 95% CI, 0.64-1.72).

Conclusions and Relevance

In this nationwide, population-based case-control study, birth by cesarean delivery was not associated with early-onset CRC compared with birth by vaginal delivery in the overall population in Sweden. However, females born by cesarean delivery had greater odds of early-onset CRC compared with individuals born through vaginal delivery. This finding suggests that early-life gut dysbiosis may contribute to early-onset CRC in females.

Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries

Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from -90% to +30%, were reported in many countries following early COVID-19 pandemic response measures ('lockdowns'). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95-0.98, P value <0.0001), second (0.96, 0.92-0.99, 0.03) and third (0.97, 0.94-1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96-1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88-1.14, 0.98), third (0.99, 0.88-1.12, 0.89) and fourth (1.01, 0.87-1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02-1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03-1.15, 0.002), third (1.10, 1.03-1.17, 0.003) and fourth (1.12, 1.05-1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways.

Severe COVID-19 during pregnancy in Sweden, Norway, and Denmark

INTRODUCTION

Pregnancy is a risk factor for severe coronavirus disease 2019 (COVID-19) and adverse pregnancy outcomes. We aimed to explore maternal characteristics, pregnancy outcomes, vaccination status, and virus variants among pregnant women admitted to intensive care units (ICU) with severe COVID-19.

MATERIAL AND METHODS

We identified pregnant women admitted to ICU in Sweden (n = 96), Norway (n = 31), and Denmark (n = 16) because of severe COVID-19, from national registers and clinical databases between March 2020 and February 2022 (Denmark), August 2022 (Sweden), or December 2022 (Norway). Their background characteristics, pregnancy outcome, and vaccination status were compared with all birthing women and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test-positive pregnant women during the same time period. We calculated the number admitted to ICU per 10 000 birthing and per 1000 SARS-CoV-2 test-positive women during the Index, Alpha, Delta, and Omicron periods.

RESULTS

Women admitted to ICU had a higher mean body mass index, were more often of non-Scandinavian origin, had on average lower education and income levels, had a higher proportion of chronic and pregnancy-related conditions, delivered preterm, had neonates with low Apgar scores, and had more infants admitted to neonatal care, compared with all birthing and test-positive pregnant women. Of those admitted to ICU, only 7% had been vaccinated before admission. Overall, the highest proportion of women admitted to ICU per birthing was during the Delta period (4.1 per 10 000 birthing women). In Norway, the highest proportion admitted to ICU per test-positive pregnant women was during the Delta period (17.8 per 1000 test-positive), whereas the highest proportion of admitted per test-positive in Sweden and Denmark was seen during the Index period (15.4 and 8.9 per 1000 test-positive, respectively).

CONCLUSIONS

Admission to ICU because of COVID-19 in pregnancy was a rare event in the Scandinavian countries, but women who were unvaccinated, of non-Scandinavian origin, and with lower socio-economic status were at higher risk of admission to ICU. In addition, women admitted to ICU for COVID-19 had higher risk of adverse pregnancy outcomes.

More than time: travel time to the delivery ward and maternal outcomes - onset of labour, postpartum haemorrhage and obstetric anal sphincter injury

BACKGROUND

Closing delivery units increases travel time for some women. Whether increased travel time is associated with maternal outcomes is important for understanding the consequences of such closures. Previous studies are limited in measuring travel time and restricted to the outcome of caesarean section.

METHODS

Our population-based cohort includes data from the Swedish Pregnancy Register for women giving birth between 2014 and 2017 (N = 364,630). We estimated travel time from home to the delivery ward using coordinate pairs of actual addresses. The association between travel time and onset of labour was modelled using multinomial logistic regression, and logistic regression was used for the outcomes postpartum haemorrhage (PPH) and obstetric anal sphincter injury (OASIS).

FINDINGS

Over three-quarters of women had ≤30 min travel time (median 13.9 min). Women who travelled ≥60 min arrived to care sooner and laboured there longer. Women with further to travel had increased adjusted odds ratio (aOR) of having an elective caesarean section (31-59 min aOR 1.11; 95% confidence interval [CI] 1.07-1.16; ≥60 min aOR 1.25; 95% CI 1.16-1.36) than spontaneous onset of labour. Women (at full term with spontaneous onset) living ≥60 min away had reduced odds of having a PPH (aOR 0.84; 95% CI 0.76-0.94) or OASIS (aOR 0.79; 95% CI 0.66-0.94).

INTERPRETATION

Longer travel time increased the odds of elective caesarean section. Women with furthest to travel arrived sooner and spent more time in care; although they had a lower risk of PPH or OASIS, they also tended to be younger, have a higher body mass index and were Nordic born.

Temporal trends in adverse pregnancy outcomes in axial spondyloarthritis in Sweden: a cohort study

BACKGROUND

Evidence on the risks associated with pregnancy and childbirth in women with axial spondyloarthritis is scarce and conflicting, with more research needed to guide policy and clinical practice. We aimed to assess the risks of adverse pregnancy outcomes in a large cohort of women with axial spondyloarthritis, and to investigate how outcomes varied over time and in relation to anti-rheumatic treatment.

METHODS

In this register-based cohort study, we included births in Sweden between April 1, 2007, and Dec 31, 2020, to women with axial spondyloarthritis and general population comparators, matched 1:10 on year of delivery, maternal age, and parity. Our main data source was the Medical Birth Register (MBR), which includes over 98% of births in Sweden and prospectively collects data on antenatal care, delivery, and foetal outcomes. The information in MBR was linked to other registers, including the National Patient Register, the Prescribed Drug Register, and registers with demographic data. Our main outcomes were the relative risks of adverse pregnancy outcomes, analysed using modified Poisson regression. We also studied how the frequency of certain adverse outcomes, as well as disease-modifying antirheumatic drug (DMARD) and non-steroidal anti-inflammatory drug treatments, changed over the study period by linear regression and loess plots.

FINDINGS

Between April 1, 2007, and Dec 31, 2020, 1580 births in women with axial spondyloarthritis recorded in MBR fulfilled the inclusion criteria and were matched with 15 792 comparator births. Among the 1580 births in women with axial spondyloarthritis, we found increased risks of preterm birth (risk ratio 1·43, 95% CI 1·13-1·80), pre-eclampsia (1·44, 1·08-1·92), elective caesarean delivery (1·59, 1·37-1·84), and serious infant infection (1·29, 1·05-1·59) compared with births in general population comparators. The risks of preterm birth, infant infection, and caesarean delivery decreased by around 0·5 percentage points annually during the study period, while the use of tumour necrosis factor inhibitors during pregnancy increased.

INTERPRETATION

In view of remaining concerns regarding safety of the use of biological DMARDs during pregnancy, we saw a reassuring trend in which pregnancy outcomes improved over time in the axial spondyloarthritis group, concurrent with increased use of biological DMARDs. If the current rate of improvement is maintained, women with axial spondyloarthritis treated in accordance with clinical guidelines might eventually not be at an increased risk of adverse pregnancy outcomes.

FUNDING

Swedish Research Council and The Swedish Rheumatism Association.

Clinical risk factors of adverse outcomes among women with COVID-19 in the pregnancy and postpartum period: a sequential, prospective meta-analysis

OBJECTIVE

This sequential, prospective meta-analysis sought to identify risk factors among pregnant and postpartum women with COVID-19 for adverse outcomes related to disease severity, maternal morbidities, neonatal mortality and morbidity, and adverse birth outcomes.

DATA SOURCES

We prospectively invited study investigators to join the sequential, prospective meta-analysis via professional research networks beginning in March 2020.

STUDY ELIGIBILITY CRITERIA

Eligible studies included those recruiting at least 25 consecutive cases of COVID-19 in pregnancy within a defined catchment area.

METHODS

We included individual patient data from 21 participating studies. Data quality was assessed, and harmonized variables for risk factors and outcomes were constructed. Duplicate cases were removed. Pooled estimates for the absolute and relative risk of adverse outcomes comparing those with and without each risk factor were generated using a 2-stage meta-analysis.

RESULTS

We collected data from 33 countries and territories, including 21,977 cases of SARS-CoV-2 infection in pregnancy or postpartum. We found that women with comorbidities (preexisting diabetes mellitus, hypertension, cardiovascular disease) vs those without were at higher risk for COVID-19 severity and adverse pregnancy outcomes (fetal death, preterm birth, low birthweight). Participants with COVID-19 and HIV were 1.74 times (95% confidence interval, 1.12-2.71) more likely to be admitted to the intensive care unit. Pregnant women who were underweight before pregnancy were at higher risk of intensive care unit admission (relative risk, 5.53; 95% confidence interval, 2.27-13.44), ventilation (relative risk, 9.36; 95% confidence interval, 3.87-22.63), and pregnancy-related death (relative risk, 14.10; 95% confidence interval, 2.83-70.36). Prepregnancy obesity was also a risk factor for severe COVID-19 outcomes including intensive care unit admission (relative risk, 1.81; 95% confidence interval, 1.26-2.60), ventilation (relative risk, 2.05; 95% confidence interval, 1.20-3.51), any critical care (relative risk, 1.89; 95% confidence interval, 1.28-2.77), and pneumonia (relative risk, 1.66; 95% confidence interval, 1.18-2.33). Anemic pregnant women with COVID-19 also had increased risk of intensive care unit admission (relative risk, 1.63; 95% confidence interval, 1.25-2.11) and death (relative risk, 2.36; 95% confidence interval, 1.15-4.81).

CONCLUSION

We found that pregnant women with comorbidities including diabetes mellitus, hypertension, and cardiovascular disease were at increased risk for severe COVID-19-related outcomes, maternal morbidities, and adverse birth outcomes. We also identified several less commonly known risk factors, including HIV infection, prepregnancy underweight, and anemia. Although pregnant women are already considered a high-risk population, special priority for prevention and treatment should be given to pregnant women with these additional risk factors.

The association between episiotomy or OASIS at vacuum extraction in nulliparous women and subsequent prelabor cesarean delivery: A nationwide observational study

INTRODUCTION

Severe perineal injuries at childbirth affect women's postnatal health, including future childbirths. First births with vacuum extraction carry an increased risk of obstetric anal sphincter injuries (OASIS). Lateral or mediolateral episiotomy at vacuum extraction may decrease the risk of OASIS. Our aim was to assess whether lateral or mediolateral episiotomy, or OASIS, at vacuum extraction in nulliparous women is associated with prelabor cesarean delivery in the subsequent childbirth.

MATERIAL AND METHODS

This is a nationwide observational study using data from the Swedish Medical Birth Register, including women having a first birth with vacuum extraction and a second birth in 2000-2014. Both births were live, single, cephalic, ≥34 gestational weeks without malformations. The association between episiotomy or OASIS in the first birth and prelabor cesarean delivery in the second birth was examined using univariate and multivariate logistic regression with inverse probability of treatment weighting, and interaction analysis. Main outcome measure was prelabor cesarean delivery in the second birth.

RESULTS

In total, 44 656 women with vacuum extraction at their first birth were included. The rate of prelabor cesarean delivery in the second birth was 5.9% (824 of 13 950) in women with episiotomy, compared with 6.0% (1830 of 30 706) in women without episiotomy. Thus, women with episiotomy did not have an increased risk of prelabor cesarean delivery (adjusted odds ratio [aOR] 1.00, 95% confidence interval [95% CI] 0.83-1.20) compared with women without episiotomy. For comparison, the rate of prelabor cesarean delivery in the second birth was 20.6% (1275 of 6176) in women with OASIS, compared with 3.6% (1379 of 38 480) in women without OASIS (aOR 6.57, 95% CI 5.97-7.23). There was no interaction between episiotomy and OASIS.

CONCLUSIONS

Lateral or mediolateral episiotomy at vacuum extraction in nulliparous women did not increase the risk of prelabor cesarean delivery in the subsequent childbirth. OASIS increased the odds of prelabor cesarean delivery more than sixfold.

Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis

INTRODUCTION

Despite a growing body of research on the risks of SARS-CoV-2 infection during pregnancy, there is continued controversy given heterogeneity in the quality and design of published studies.

METHODS

We screened ongoing studies in our sequential, prospective meta-analysis. We pooled individual participant data to estimate the absolute and relative risk (RR) of adverse outcomes among pregnant women with SARS-CoV-2 infection, compared with confirmed negative pregnancies. We evaluated the risk of bias using a modified Newcastle-Ottawa Scale.

RESULTS

We screened 137 studies and included 12 studies in 12 countries involving 13 136 pregnant women.Pregnant women with SARS-CoV-2 infection-as compared with uninfected pregnant women-were at significantly increased risk of maternal mortality (10 studies; n=1490; RR 7.68, 95% CI 1.70 to 34.61); admission to intensive care unit (8 studies; n=6660; RR 3.81, 95% CI 2.03 to 7.17); receiving mechanical ventilation (7 studies; n=4887; RR 15.23, 95% CI 4.32 to 53.71); receiving any critical care (7 studies; n=4735; RR 5.48, 95% CI 2.57 to 11.72); and being diagnosed with pneumonia (6 studies; n=4573; RR 23.46, 95% CI 3.03 to 181.39) and thromboembolic disease (8 studies; n=5146; RR 5.50, 95% CI 1.12 to 27.12).Neonates born to women with SARS-CoV-2 infection were more likely to be admitted to a neonatal care unit after birth (7 studies; n=7637; RR 1.86, 95% CI 1.12 to 3.08); be born preterm (7 studies; n=6233; RR 1.71, 95% CI 1.28 to 2.29) or moderately preterm (7 studies; n=6071; RR 2.92, 95% CI 1.88 to 4.54); and to be born low birth weight (12 studies; n=11 930; RR 1.19, 95% CI 1.02 to 1.40). Infection was not linked to stillbirth. Studies were generally at low or moderate risk of bias.

CONCLUSIONS

This analysis indicates that SARS-CoV-2 infection at any time during pregnancy increases the risk of maternal death, severe maternal morbidities and neonatal morbidity, but not stillbirth or intrauterine growth restriction. As more data become available, we will update these findings per the published protocol.

The Swedish medical birth register during five decades: documentation of the content and quality of the register

Pregnancy-related factors are important for short- and long-term health in mothers and offspring. The nationwide population-based Swedish Medical Birth Register (MBR) was established in 1973. The present study describes the content and quality of the MBR, using original MBR data, Swedish-language and international publications based on the MBR.The MBR includes around 98% of all births in Sweden. From 1982 onwards, the MBR is based on prospectively recorded information in standardized antenatal, obstetric, and neonatal records. When the mother and infant are discharged from hospital, this information is forwarded to the MBR, which is updated annually. Maternal data include information from first antenatal visit on self-reported obstetric history, infertility, diseases, medication use, cohabitation status, smoking and snuff use, self-reported height and measured weight, allowing calculation of body mass index. Birth and neonatal data include date and time of birth, mode of delivery, singleton or multiple birth, gestational age, stillbirth, birth weight, birth length, head circumference, infant sex, Apgar scores, and maternal and infant diagnoses/procedures, including neonatal care. The overall quality of the MBR is very high, owing to the semi-automated data extraction from the standardized regional electronic health records, Sweden's universal access to antenatal care, and the possibility to compare mothers and offspring to the Total Population Register in order to identify missing records. Through the unique personal identity numbers of mothers and live-born offspring, the MBR can be linked to other health registers. The Swedish MBR contains high-quality pregnancy-related information on more than 5 million births during five decades.

Abstract P074: Pregnancy and neonatal outcomes among early-onset colorectal cancer survivors: a nationwide case-control study

Purpose: Early-onset colorectal cancer (CRC diagnosed before age 50) has risen worldwide, with an increasing number of survivors of reproductive age. We aimed to investigate the risk of adverse pregnancy and neonatal outcomes among early-onset CRC survivors. Methods: We conducted a nationwide case-control study of 207 births in women with early-onset CRC and 1019 births in women without CRC from the general Swedish population (1992-2019), matched on age, calendar year of birth, parity, and county of residence. To control for genetic susceptibility and shared childhood exposures, we additionally identified 146 births in female siblings of the CRC survivors. Early-onset CRC cases were identified through the Swedish Cancer Register (1969-2019), and siblings were identified through the Swedish Multi-generation Register. Maternal characteristics and neonatal outcomes were retrieved from the Swedish Medical Birth Register and National Patient Register. Using conditional logistic regression, we estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Results: Compared to women without prior CRC, early-onset CRC survivors who gave birth had increased risk of pre-eclampsia (aOR 2.52, 95% CI 1.25 to 5.08), induced labor (aOR 1.64, 95% CI 1.09 to 2.46) and emergency Cesarean section (aOR 1.79, 95% CI 1.17 to 2.75), after adjustment for maternal education level, country of birth, body mass index and smoking in early pregnancy, and comorbidities. Sibling analyses showed similar trends, especially for higher risk of induced labor (aOR 2.58, 95% CI 1.03 to 6.49). Maternal history of early-onset CRC was also associated with offspring preterm birth (aOR 2.31, 95% CI 1.34 to 3.99) and low birth weight (aOR 2.95, 95% CI 1.40 to 6.21), and risks were particularly pronounced for medically indicated preterm birth (aOR 4.48, 95% CI 2.05 to 9.79). No significant associations were found for small for gestational age birth, low Apgar score, and congenital malformations. Conclusion: In this population-based study, history of early-onset CRC was associated with increased risk of adverse pregnancy outcomes, including pre-eclampsia, induction of labor, and emergency Cesarean section. Offspring to mothers with early-onset CRC also had increased risk of medically indicated preterm birth and neonatal low birth weight.

Citation Format: Yin Cao, Stephanie Zhao, Tomas S. Bexelius, Jonas Söderling, Mengyao Shi, Bjorn Roelstraete, Barbara B. Warner, Olof Stephansson, Jonas F. Ludvigsson. Pregnancy and neonatal outcomes among early-onset colorectal cancer survivors: a nationwide case-control study. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P074.

Pregnancy Outcomes in Women With Autoimmune Hepatitis - A Nationwide Population-based Cohort Study With Histopathology

BACKGROUND & AIMS

Autoimmune hepatitis (AIH) is a chronic inflammatory liver condition that predominantly affects women. However, pregnancy risks remain unclear.

METHODS

A nationwide population-based cohort study (ESPRESSO) in Sweden from 1992 to 2016 including 309 singleton births in women with AIH and 1532 matched births in women from the general population was performed. AIH was diagnosed as a combination of administrative coding from medical diagnosis of AIH and liver biopsy data from Sweden's 28 pathology departments. Using conditional logistic regression, odds ratios (ORs) for adverse pregnancy outcomes were determined.

RESULTS

Among 306 live births to women with AIH, 51 (16.7%) were preterm, compared with 70 of 1524 (4.6%) reference births. This corresponded to an OR of 5.10 for preterm birth (95% confidence interval [CI], 3.29-7.92), with similar odds using sibling comparators. Women with AIH with and without cirrhosis had similar odds for preterm birth. The AIH association was particularly strong with medically indicated preterm birth (OR, 13.01; 95% CI, 5.50-30.79). AIH was associated with low birth weight (OR, 5.31; 95% CI, 2.82-9.99) and low 5-minute Apgar score (OR, 3.46; 95% CI, 1.14-10.49) offspring, but we found no association with congenital malformations (OR, 1.14; 95% CI, 0.68-1.91), small for gestational age (OR, 1.04; 95% CI, 0.38-2.85), stillbirth (OR, 0.59; 95% CI, 0.02-18.88), or neonatal death (OR, 7.42; 95% CI, 0.65-84.25). Maternal AIH was linked to an increased odds of cesarean section (OR, 1.44; 95% CI, 1.04-2.00) and preeclampsia (OR, 3.65; 95% CI, 2.01-6.64), but not to gestational diabetes.

CONCLUSIONS

Maternal AIH was associated with a 5-fold higher odds of preterm birth, and cirrhosis at diagnosis did not add to the impact of AIH on preterm birth. Future studies are needed to understand how to reduce this risk.

The Stockholm-Gotland perinatal cohort-A population-based cohort including longitudinal data throughout pregnancy and the postpartum period

BACKGROUND

Register-based reproductive and perinatal databases rarely contain detailed information from medical records or repeated measurements throughout pregnancy and delivery. This lack of enriched pregnancy and birth data led to the initiation of the Swedish Stockholm-Gotland Perinatal Cohort (SGPC).

OBJECTIVES

To describe the strengths of the SGPC, as well as the unique research questions that can be addressed using this cohort.

POPULATION

The SGPC is a prospectively collected, population-based cohort that includes all births (from 22 completed gestational weeks onwards) between 1 January 2008 and 15 June 2020 in the Stockholm and Gotland regions of Sweden (N 335,153 singleton and N 11,025 multiple pregnancies).

DESIGN

Descriptive study.

METHODS

The SGPC is based on the electronic medical records of women and their infants. The medical record system is used for all antenatal clinic visits and admissions, delivery and neonatal admissions, as well as postpartum clinical visits. SGPC has been further enriched with data linkages to 10 Swedish National Health Care and Quality Registers.

PRELIMINARY RESULTS

In contrast to other reproductive and perinatal databases available in Sweden, including the Medical Birth Register and the Pregnancy Register, SGPC contains highly detailed medical record data, including time-varying serial measurements for physiological parameters throughout pregnancy, delivery, and postpartum, for both mother and infant. These strengths have enabled studies that were previously inconceivable; the effects of serial measurements of pregnancy weight gain, changes in haemoglobin counts and blood pressure during pregnancy, fetal weight estimations by ultrasound, duration of stages and phases of labour, cervical dilatation and oxytocin use during delivery, and constructing reference curves for umbilical cord pH.

CONCLUSIONS

The SGPC-with its rich content, repeated measurements and linkages to numerous health care and quality registers-is a unique cohort that enables high-quality perinatal studies that would otherwise not be possible.

Fetal death after the introduction of COVID-19 mitigation measures in Sweden, Denmark and Norway: a registry-based study

It remains unclear whether the rate of fetal death has changed during the COVID-19 pandemic. We assessed the impact of COVID-19 mitigation measures on fetal death in Sweden (449,347 births), Denmark (290,857 pregnancies) and Norway (261,057 pregnancies) using robust population-based registry data. We used Cox regression to assess the impact of the implementation of pandemic mitigation measures on March 12th, 2020, on miscarriage (fetal loss before gestational week 22) and stillbirth (fetal loss after gestational week 22). A total of 11% of 551,914 pregnancies in Denmark and Norway ended in miscarriage, while the proportion of stillbirths among 937,174 births across the three countries was 0.3%. There was no difference in the risk of fetal death during the year following pandemic mitigation measures. For miscarriage, the combined hazard ratio (HR) for Norway and Denmark was 1.01 (95% CI 0.98, 1.03), and for stillbirth, the combined HR for all three countries was 0.99 (95% CI 0.89, 1.09). We observed a slightly decreased risk of miscarriage during the first 4 months, with an HR of 0.94 (95% CI 0.90, 0.99) after lockdown. In conclusion, the risk of fetal death did not change after the implementation of COVID-19 pandemic mitigation measures in the three Scandinavian countries.

Histological remission in inflammatory bowel disease and risk of adverse pregnancy outcomes: A nationwide study

BACKGROUND

Inflammatory bowel disease (IBD) has been linked to adverse pregnancy outcomes, but it is unclear how risks vary by histological activity.

METHODS

We performed a nationwide study of Swedish women diagnosed with IBD 1990-2016 and a pre-pregnancy (<12 months) colorectal biopsy with vs. without histological inflammation (1223 and 630 births, respectively). We also examined pregnancy outcomes in 2007-2016 of women with vs. without clinically active IBD (i.e., IBD-related hospitalization, surgery, or medication escalation) <12 months before pregnancy (2110 and 4993 births, respectively). Accounting for smoking, socio-demographics, and comorbidities, generalized linear models estimated adjusted risk ratios (aRRs) for preterm birth (<37 gestational weeks) and small-for-gestational age (SGA, <10th percentile weight for age).

FINDINGS

Of infants to women with vs. without histological inflammation, 9.6% (n = 117) and 6.5% (n = 41) were preterm, respectively (aRR = 1.46; 95%CI = 1.03-2.06). Histological inflammation was associated with preterm birth in ulcerative colitis (UC) (aRR = 1.64; 95%CI = 1.07-2.52), especially extensive colitis (aRR = 2.37; 95%CI = 1.12-5.02), but not in Crohn's disease (aRR = 0.99; 95%CI = 0.55-1.78). Of infants to women with vs. without histological inflammation, 116 (9.6%) and 56 (8.9%), respectively, were SGA (aRR = 1.09; 95%CI = 0.81-1.47). Clinically active disease before pregnancy was linked to preterm birth (aRR = 1.42; 95%CI = 1.20-1.69), but not to SGA birth (aRR = 1.13; 95%CI = 0.96-1.32). Finally, of infants to women without clinical activity, histological inflammation was not significantly associated with preterm birth (aRR = 1.20; 95%CI = 0.68-2.13).

INTERPRETATION

Histological and clinical activity in IBD, especially in UC, were risk factors for preterm birth. Further research is needed to determine the importance of pre-pregnancy histological activity in women without clinically-defined disease activity.

FUNDING

The Swedish Society of Medicine.

Associations between ambient temperature and risk of preterm birth in Sweden: A comparison of analytical approaches

BACKGROUND

Evidence indicates that high temperatures are a risk factor for preterm birth. Increasing heat exposures due to climate change are therefore a concern for pregnant women. However, the large heterogeneity of study designs and statistical methods across previous studies complicate interpretation and comparisons. We investigated associations of short-term exposure to high ambient temperature with preterm birth in Sweden, applying three complementary analytical approaches.

METHODS

We included 560,615 singleton live births between 2014 and 2019, identified in the Swedish Pregnancy Register. We estimated weekly mean temperatures at 1-km² spatial resolution using a spatiotemporal machine learning methodology, and assigned them at the residential addresses of the study participants. The main outcomes of the study were gestational age in weeks and subcategories of preterm birth (<37 weeks): extremely preterm birth (<28 weeks), very preterm birth (from week 28 to <32), and moderately preterm birth (from week 32 to<37). Case-crossover, quantile regression and time-to-event analyses were applied to estimate the effects of short-term exposure to increased ambient temperature during the week before birth on preterm births. Furthermore, distributed lag nonlinear models (DLNM) were applied to identify susceptibility windows of exposures throughout pregnancy in relation to preterm birth.

RESULTS

A total of 1924 births were extremely preterm (0.4%), 2636 very preterm (0.5%), and 23,664 moderately preterm (4.2%). Consistent across all three analytical approaches (case-crossover, quantile regression and time-to-event analyses), higher ambient temperature (95th vs 50th percentile) demonstrated increased risk of extremely preterm birth, but associations did not reach statistical significance. In DLNM models, we observed no evidence to suggest an increased effect of high temperature on preterm birth risk. Even so, a suggested trend was observed in both the quantile regression and time-to-event analyses of a higher risk of extremely preterm birth with higher temperature during the last week before birth.

CONCLUSIONS

In Sweden, with high quality data on exposure and outcome, a temperate climate and good quality ante-natal health care, we did not find an association between high ambient temperatures and preterm births. Results were consistent across three complementary analytical approaches.

Risk of gestational diabetes mellitus in relation to early pregnancy and gestational weight gain before diagnosis: A population-based cohort study

INTRODUCTION

Gestational diabetes mellitus (GDM) is a common pregnancy complication associated with adverse consequences for the mother and offspring in both short and long term. The aim of this study was to investigate associations between risk of GDM and gestational weight gain in early pregnancy and before diagnosis.

MATERIAL AND METHODS

Our population-based cohort study included 131 164 singleton pregnancies in the Stockholm-Gotland region in Sweden from 2008 through 2013. The exposures were weight gain in early pregnancy (<22 weeks) and weight gain before diagnosis, standardized into gestational age-specific z scores. The outcome was GDM. We used logistic regression models with a generalized estimating equations method to estimate odds ratios with 95% confidence intervals for GDM, stratified by early-pregnancy body mass index (BMI) category.

RESULTS

Above average weight gain before diagnosis (z score >0) was associated with increased risk of GDM among all BMI groups except for obese III. Early gestational weight gain above average was associated with increased risk for GDM in overweight women. Below average weight gain before diagnosis (z score <0) was only associated with decreased risk of GDM in obese III. Early gestational weight gain below average was associated with reduced risks of GDM in obese class I, II, and III women.

CONCLUSIONS

The risk of GDM increased with higher weight gain before diagnosis in all BMI groups except obese class III, whereas the risk was reduced with lower weight gain before diagnosis in obese III women only. The risk of GDM increased with higher early gestational weight gain in overweight women, while the risk was reduced with lower early gestational weight gain among obese women. Obese women may benefit from lower weight gain, especially in early pregnancy.

Crude and adjusted comparisons of cesarean delivery rates using the Robson classification: A population-based cohort study in Canada and Sweden, 2004 to 2016

BACKGROUND

The Robson classification has become a global standard for comparing and monitoring cesarean delivery (CD) rates across populations and over time; however, this classification does not account for differences in important maternal, fetal, and obstetric practice factors known to impact CD rates. The objectives of our study were to identify subgroups of women contributing to differences in the CD rate in Sweden and British Columbia (BC), Canada using the Robson classification and to estimate the contribution of maternal, fetal/infant, and obstetric practice factors to differences in CD rates between countries and over time.

METHODS AND FINDINGS

We conducted a population-based cohort study of deliveries in Sweden (January 1, 2004 to December 31, 2016; n = 1,392,779) and BC (March 1, 2004 to April 31, 2017; n = 559,205). Deliveries were stratified into Robson categories and the CD rate, relative size of each group and its contribution to the overall CD rate were compared between the Swedish and the Canadian cohorts. Poisson and log-binomial regression were used to assess the contribution of maternal, fetal, and obstetric practice factors to spatiotemporal differences in Robson group-specific CD rates between Sweden and BC. Nulliparous women comprised 44.8% of the study population, while women of advanced maternal age (≥35 years) and women with overweight/obesity (≥25 kg/m2) constituted 23.5% and 32.4% of the study population, respectively. The CD rate in Sweden was stable at approximately 17.0% from 2004 to 2016 (p for trend = 0.10), while the CD rate increased in BC from 29.4% to 33.9% (p for trend < 0.001). Differences in CD rates between Sweden and BC varied by Robson group, for example, in Group 1 (nullipara with a term, single, cephalic fetus with spontaneous labor), the CD rate was 8.1% in Sweden and 20.4% in BC (rate ratio [RR] for BC versus Sweden = 2.52, 95% confidence interval [CI] 2.49 to 2.56, p < 0.001) and in Group 2 (nullipara, single, cephalic fetus, term gestation with induction of labor or prelabor CD), the rate of CD was 37.3% in Sweden and 45.9% in BC (RR = 1.23, 95% CI 1.22 to 1.25, p < 0.001). The effect of adjustment for maternal characteristics (e.g., age, body mass index), maternal comorbidity (e.g., preeclampsia), fetal characteristics (e.g., head position), and obstetric practice factors (e.g., epidural) ranged from no effect (e.g., among breech deliveries; Groups 6 and 7) to explaining up to 5.2% of the absolute difference in the CD rate (Group 2: adjusted CD rate in BC 40.7%, adjusted RR = 1.09, 95% CI 1.08 to 1.12, p < 0.001). Adjustment also explained a substantial fraction of the temporal change in CD rates among some Robson groups in BC. Limitations of the study include a lack of information on intrapartum details, such as labor duration as well as maternal and perinatal outcomes associated with the observed differences in CD rates.

CONCLUSIONS

In this study, we found that several factors not included in the Robson classification explain a significant proportion of the spatiotemporal difference in CD rates in some Robson groups. These findings suggest that incorporating these factors into explanatory models using the Robson classification may be useful for ensuring that public health initiatives regarding CD rates are evidence informed.

Tick-borne encephalitis in pregnant women – a mini narrative review

Tick-borne encephalitis (TBE) incidence has been increasing in Europe the last decades, but very few cases in pregnant women have been described. We present two cases and describe the serology of both mother and infant at the time of diagnosis and delivery, as well as at months 3, 6, 9, and 12 of follow-up. In both cases, pregnancies and infants developed normally. The mothers had moderate-to severe symptoms of TBE and were positive for IgM and IgG at the time of diagnosis, and throughout the follow up period whilst both infants were PCR- and IgM-negative and positive for IgG during their first months in life. Declining IgG titres were seen in the infants during follow-up until they became negative at the age of nine months. TBE IgG was vertically transmitted in these two cases of infants born to TBE-infected mothers.

Time of delivery among low-risk women at 37-42 weeks of gestation and risks of stillbirth and infant mortality, and long-term neurological morbidity

BACKGROUND

The most important knowledge gap in connection with obstetric management for time of delivery in term low-risk pregnancies relates to the absence of information on long-term neurodevelopmental outcomes.

OBJECTIVES

We examined risks of stillbirth, infant mortality, cerebral palsy (CP) and epilepsy among low-risk pregnancies.

METHODS

In this population-based Swedish study, we identified, from 1998 to 2019, 1,773,269 singleton infants born between 37 and 42 completed weeks in women with low-risk pregnancies. Poisson log-linear regression models were used to examine the association between gestational age at delivery and stillbirth, infant mortality, CP and epilepsy. Adjusted rate ratios (RR) and 95% confidence intervals expressing the effect of birth at a particular gestational week compared with birth at a later gestational week were estimated.

RESULTS

Compared with those born at a later gestation, RRs for stillbirth and infant mortality were higher among births at 37 weeks' and 38 weeks' gestation. The RRs for infant mortality were approximately 20% and 25% lower among births at 40 or 41 weeks compared with those born at later gestation, respectively. Infants born at 37 and 38 weeks also had higher RRs for CP (vs infants born at ≥38 and ≥39 weeks, respectively), while those born at 39 gestation had similar RRs (vs infants born at ≥40 weeks); infants born at 40 and 41 weeks had lower RRs of CP (vs those born at ≥41 and 42 weeks, respectively). The RRs for epilepsy were higher in those born at 37 and 38 weeks compared with those born at later gestation.

CONCLUSIONS

Among low-risk pregnancies, birth at 37 or 38 completed weeks' gestation is associated with increased risks of stillbirth, infant mortality and neurological morbidity, while birth at 39-40 completed weeks is associated with reduced risks compared with births at later gestation.

OP0126 ARE WOMEN WITH SPONDYLOARTHRITIS AT INCREASED RISK OF ADVERSE MATERNAL AND INFANT OUTCOMES? – A SWEDISH COHORT STUDY

Background

An increased risk of adverse pregnancy and neonatal outcomes has been reported for pregnancies in women with several rheumatic diseases including rheumatoid arthritis and psoriatic arthritis. In spondyloarthritis (SpA), findings have not been uniform, with some studies reporting increased risks of Cesarean delivery, preterm birth, infants born small-for-gestational-age (SGA), and gestational diabetes- and hypertension, while others have failed to identify any significant differences between women with SpA and general population control women. Most studies reporting no differences have either been small or lacked an appropriate comparison group [1].

Objectives

To assess the risk of adverse maternal and infant pregnancy outcomes in women with SpA compared to the general population.

Methods

In this nationwide register-based study, we included singleton births between April 2007 and December 2019 in women diagnosed with ankylosing spondylitis (AS; ICD-10 codes M45 or M08.1) or undifferentiated SpA (uSpA; ICD-10 codes M46.8 or M46.9). This was performed through linkage between the National Patient Register and the Medical Birth Register. Each birth was matched on birth year, maternal age, and parity to ten comparator births in women free from chronic inflammatory arthritis at time of birth. Relative risks (RR) of adverse outcomes were estimated by Poisson regression, adjusting for maternal country of birth, BMI, smoking in early pregnancy, educational level, and disposable income in the year before pregnancy.

Results

Women with SpA (n=1394) were found to be at increased risk of several adverse outcomes compared to general population comparators (n=13932), as displayed in the Figure 1. Women with SpA had an increased risk of gestational diabetes (adjusted RR 1.88 [95% CI 1.10; 2.56]), elective and emergency Cesarean delivery (adjusted RR 1.54 [95% CI 1.32; 1.79] and 1.23 [95% CI 1.02; 1.48], respectively), and moderately preterm birth (adjusted RR 1.52 [95% CI 1.18; 1.97]). An association was seen with both spontaneous and medically indicated preterm birth, but the increase was only significant for spontaneous preterm birth. The risk estimate for preeclampsia was also increased, but failed to reach significance (adjusted RR 1.32 [95% CI 0.96; 1.81]). Infants to mothers with SpA were not more likely to be born SGA, but there was a slightly increased risk estimate of infection during their first year of life (adjusted RR 1.23 [95% CI 0.98; 1.53]).

Figure 1.

Number of events of adverse pregnancy outcomes among a nationwide cohort of births (n=1394) in Swedish women with SpA and comparator births (n=13932, matched 1:10 on birth year, maternal age, and parity). Relative risks from Poisson regression, adjusted for maternal country of birth, BMI, smoking in early pregnancy, educational level, and disposable income in the year before pregnancy.

Conclusion

While most pregnancies in women with SpA are uneventful, there is an increased risk for a number of adverse pregnancy outcomes. The increased risks for both emergency Cesarean delivery and spontaneous preterm birth suggest that these differences are not only driven by a different management of SpA pregnancies.

References

[1]Mokbel A, Lawson DO, Farrokhyar F. Pregnancy outcomes in women with ankylosing spondylitis: a scoping literature and methodological review. Clinical Rheumatology 2021;40(9):3465-80.

Disclosure of Interests

None declared

Exposure to Allergen-Specific Immunotherapy in Pregnancy and Risk of Congenital Malformations and Other Adverse Pregnancy Outcomes

BACKGROUND

Owing to insufficient data, current guidelines recommend against initiating allergen-specific immunotherapy (AIT) during pregnancy but suggest that well-tolerated ongoing immunotherapy may be continued.

OBJECTIVE

To evaluate the safety of AIT in pregnancy, especially the risk for congenital malformations.

METHODS

This nationwide Swedish cohort study identified pregnancies exposed to AIT, both subcutaneous and sublingual, through the Swedish Medical Birth register and the Prescribed Drug Register between 2005 and 2014. Information on congenital malformations in offspring was retrieved from the National Patient Register. Using the personal identity number, we linked data between registers. Using logistic regression, we calculated odds ratios (ORs) with 95% CIs for congenital malformations and other adverse pregnancy outcomes after adjusting for potential confounders.

RESULTS

From 2005 to 2014, we identified 924,790 singleton pregnancies. Among these, 743 pregnancies had been exposed to AIT 3 months before conception up until gestational week 22. Allergen-specific immunotherapy in pregnancy was not linked to congenital malformations (OR = 0.90; 95% CI, 0.63-1.27) or other adverse pregnancy outcomes (preterm birth: OR = 0.98; 95% CI, 0.71-1.35; stillbirth: OR = 0.79; 95% CI, 0.26-2.47; or cesarean delivery: OR = 0.91; 95% CI, 0.76-1.09). Stratification by route of immunotherapy, subcutaneous or sublingual, resulted in similar ORs. Restricting the pregnancy cohort to women with asthma or pulmonary disease, nulliparous women, births in 2012 to 2014, or Swedish-born women yielded similar results.

CONCLUSIONS

This nationwide study found no evidence of congenital malformations or other adverse pregnancy outcomes in women treated with AIT in pregnancy.

Association between first and second stage of labour duration and mode of delivery: A population-based cohort study

BACKGROUND

Active first stage of labour duration can widely vary between women. However, the nature of the relationship between the active first stage and second stage of labour duration is sparsely studied.

OBJECTIVES

To determine whether active first stage of labour duration (i) influences second stage of labour duration; and (ii) is associated with mode of delivery.

METHODS

A population-based cohort study of 13,379 women primiparous women, with spontaneous start in Stockholm-Gotland Region, Sweden, between 2008 and 2014. Duration of the active first stage of labour was examined in relation to second-stage duration using univariate and multivariable quantile regressions, with the first quartile (first stage duration) as the reference. Nonlinearity of associations was tested by restricted cubic splines. Association between active first-stage duration with mode of delivery was estimated using a multinomial logistic regression based on adjusted odds ratios.

RESULTS

Longer active first stage of labour duration was linearly associated with longer second stage of labour duration until approximately 12 h of active first stage of labour duration. After 12 h, a non-linear trend is seen, demonstrated by a plateau in the second-stage duration. In addition, longer active first stage of labour duration was associated with increased occurrence of operative vaginal delivery (adjusted odds ratio 3.36, 95% confidence interval [CI] 2.89, 3.89) and caesarean delivery (adjusted odds ratio 4.75, 95% CI 3.85, 5.80).

CONCLUSIONS

Among primiparous women with spontaneous onset of labour, longer active first stage of labour duration was associated with both longer second stage of labour duration and higher odds of operative delivery. This study contributes with findings, which may inform future discussions regarding how to properly account for second-stage duration, with applications in obstetric and perinatal epidemiology.