Induced Labor in Sweden, 1999-2012: A Population-Based Cohort Study

Neonatal outcomes of elective labor induction in low-risk term pregnancies

The rate of labor induction has increased in recent years. The results of previously conducted studies examining associations between elective induction of labor (IOL) and neonatal outcomes have been contradictory. The aim of this study was to examine the intrinsic neonatal risks following IOL. We conducted a population-based cohort study, including all women with recorded low-risk singleton pregnancies at a gestational age between 37 + 0 and 41 + 6 weeks in Sweden from 1999 to 2017. Data were collected from the Swedish Medical Birth register. Two study groups were compared-the elective induction group with the spontaneous labor onset group. The results showed that the rate of elective IOL increased from 7.2% in 1999 to 16.4% in 2017. Elective IOL was associated with a higher OR for chorioamnionitis, bacterial sepsis, intracranial hemorrhage, assisted ventilation, hyperbilirubinemia, APGAR < 7 at 5 min, and neonatal seizures compared to deliveries with spontaneous labor onset. Regarding mortality outcomes, no significant differences were shown between the groups for either early term or full-term deliveries. We conclude that IOL is associated with neonatal complications, although causality could not be established in this observational study. It is important to be aware of the increased risk and perform IOL with caution.

Disruption of physiological labour; - A population register-based study among nulliparous women at term

OBJECTIVES

Current labour practices have seen an acceleration in interventions to either initiate, monitor, accelerate, or terminate the physiological process of pregnancy and childbirth. This study aimed to describe and analyse the use of interventions in childbirth in Denmark over almost two decades (2000-2017). We also examined the extent to which contemporary care adheres to current international recommendations towards restricted use of interventions.

STUDY DESIGN

A national retrospective Danish register-based cohort study including all nulliparous women with term births with singleton pregnancy and a foetus in cephalic between the years 2000 and 2017 (n = 380,326 births). Multivariate regression analyses with adjustment for change in population were performed.

MAIN OUTCOME MEASURES

Induction of labour, epidural analgesia, and augmentation of labour.

RESULTS

Between 2000/2001 and 2016/2017, the prevalence increased for induction of labour from 5.1% to 22.8%, AOR 4.84, 95% CI [4.61-5.10], epidural analgesia from 10.5% to 34.3% (AOR 4.10, 95% CI [3.95-4.26]), and augmentation of labour decreased slightly from 40.1% to 39.3% (AOR 0.84, 95% CI [0.81-0.86]). Having more than one of the three mentioned interventions increased from 12.8% in to 30.9%.

CONCLUSIONS

The number of interventions increased during the study period as well as the number of interventions in each woman. As interventions may interfere in physiological labour and carry the risk of potential short- and long-term consequences, the findings call for a careful re-evaluation of contemporary maternity care with a "first, do no harm" perspective.

Stillbirth and subsequent pregnancy outcome - a cohort from a large tertiary referral hospital

Objectives This study aimed to assess pregnancy and delivery outcomes in women with a history of stillbirth in a large tertiary referral hospital. Methods This was a retrospective study from Helsinki University Hospital, Finland. The cohort comprised 214 antepartum singleton stillbirths in the period 2003-2015 (case group). Of these, 154 delivered by the end of 2017. Adverse pregnancy outcomes were compared to those in singleton pregnancies of parous women in Finland from the Finnish Medical Birth Register (reference group). Results The rates of adverse pregnancy outcomes were higher among case women for preeclampsia (3.3 vs. 0.9%, P = 0.002), preterm birth (8.5 vs. 3.9%, P = 0.004), small-for-gestational-age (SGA) children (7.8 vs. 2.2%, P < 0.001) and stillbirth (2.7 vs. 0.3%, P < 0.001). There were four preterm recurrent stillbirths. Induction of labor was more common among case women than parous women in the reference group (49.4 vs. 18.3%, P < 0.001). Duration of pregnancy was shorter among case women (38.29 ± 3.20 vs. 39.27 ± 2.52, P < 0.001), and mean birth weight was lower among newborns of the case women (3274 ± 770 vs. 3491 ± 674 g, P < 0.001). Conclusion Although the rates for adverse pregnancy outcomes were higher compared to the parous background population, the overall probability of a favorable outcome was high. The risk of recurrent premature stillbirth in our cohort was higher than that for parous women in general during the study period. No recurrent term stillbirths occurred, however.

Routine induction in late-term pregnancies: follow-up of a Danish induction of labour paradigm

OBJECTIVES

For many years, routine elective induction of labour at gestational week (GW) 42+0 has been recommended in Denmark. In 2011, a more proactive protocol was introduced aimed at reducing stillbirths, and practice changed into earlier routine induction, i.e. between 41+3 and 41+5 GW. The present study evaluates a national change in induction of labour regime. The trend of maternal and neonatal consequences are monitored in the preintervention period (2000-2010) compared with the postintervention period (2012-2016).

DESIGN

A national retrospective register-based cohort study.

SETTING

Denmark.

PARTICIPANTS

All births in Denmark 41+3 to 45+0 GWs between 2000 and 2016 (N = 152 887).

OUTCOME MEASURES

Primary outcomes: stillbirths, perinatal death, and low Apgar scores. Additional outcomes: birth interventions and maternal outcomes.

RESULTS

For the primary outcomes, no differences in stillbirths, perinatal death, and low Apgar scores were found comparing the preintervention and postintervention period. Of additional outcomes, the trend changed significantly postintervention concerning use of augmentation of labour, epidural analgesia, induction of labour and uterine rupture (all p<0.05). There was no significant change in the trend for caesarean section and instrumental birth. Most notable for clinical practice was the increase in induction of labour from 41% to 65% (p<0.01) at 41+3 weeks during 2011 as well as the rare occurrence of uterine ruptures (from 2.6 to 4.2 per thousand, p<0.02).

CONCLUSIONS

Evaluation of a more proactive regimen recommending induction of labour from GW 41+3 compared with 42+0 using national register data found no differences in neonatal outcomes including stillbirth. The number of women with induced labour increased significantly.

Symptoms of Discomfort and Problems Associated with Mode of Delivery During the Puerperium: An Observational Study

Despite abundant literature on antenatal and delivery care received by pregnant women, there is a wide knowledge gap on the prevalence of symptoms of discomfort or problems during the postpartum period and their relationship with the mode of delivery. This cross-sectional study, carried out with 3324 participants in Spain in 2017, aimed to investigate the association between the mode of delivery and self-reported postpartum symptoms of discomfort and maternal problems during the puerperium. An ad hoc online questionnaire was used to collect data on socio-demographic and obstetric variables, symptoms of discomfort, and maternal problems during the puerperium. The crude odds ratios (OR) and adjusted OR (aOR) and their 95% confidence intervals (95%CI) were calculated using binary logistic regression. In total, 3324 women participated. Compared to a normal vaginal delivery, having a cesarean section was associated with increased odds of an infected surgical wound (aOR: 11.62, 95%CI: 6.77–19.95), feeling sad (aOR: 1.31, 23 95%CI: 1.03–1.68), and symptoms of post-traumatic stress (aOR: 4.64, 95%CI: 2.94–7.32). Instrumental delivery vs. normal vaginal delivery was a risk factor for constipation (aOR: 1.35 95%CI: 25 1.10–1.66), hemorrhoids (aOR: 1.28, 95%CI: 1.04–1.57), urinary incontinence (aOR: 1.30, 95%CI: 26 1.05–1.61), and fecal incontinence (aOR: 1.94, 95%CI: 1.29–2.92) during the puerperium. Women who gave delivery via cesarean section or instrumental delivery had higher incidences of infection and psychological alterations than those who had a normal vaginal delivery. Identifying women at risk of giving birth by cesarean section and informing them about subsequent symptoms of discomfort and maternal problems during the puerperium must be included in pregnancy health program policies and protocols to allow women to make informed decisions regarding their birthing plan.

Secular trends of birthweight in boys from 1950 to 2010

BACKGROUND

Birthweight is an indicator of fetal development and intrauterine conditions and is associated with future health outcomes. Secular birthweight trends prior to the 1970s are mostly unknown. Our aim was to explore secular birthweight trends in Swedish boys from 1950 to 2010.

METHODS

We have collected detailed growth data including birthweight from archived School Health Care records for children born in Gothenburg from 1946 and onwards and established a unique population-based cohort, the Body Mass Index Epidemiology Study (BEST). The birthweight cohort spans six decades (1950-2010) and includes 46,548 boys.

RESULTS

The mean birthweight of the complete study cohort was 3580 ± 562 g. Linear regression analysis of the entire period revealed a minimal negative secular trend for birthweight (BETA = -0.4 g/year; p < 0.01). However, three distinct trends appeared during sub-periods: a decrease 1950-80, an increase 1980-2000 and another decrease 2000-2010.

CONCLUSION

We demonstrate that birthweight in boys has undergone periodic decreases and subsequent increases, but the overall trend from the 1950s to the present is stable.

Standard and adjusted criteria for the use of the misoprostol vaginal insert for labor induction: a comparative cohort study

Objective To compare the efficacy of misoprostol vaginal insert (MVI) for labor induction using standard and adjusted criteria. Methods A single-center, comparative cohort study using a consecutive series of pregnant women ≥37/0 weeks undergoing labor induction with either standard criteria for MVI (administration for up to 24 h; MVI-24) or with adjusted criteria (MVI administration for a maximum of 10 h; MVI-10) conducted at a tertiary academic center in Germany. The primary outcomes were the time from start of induction to any delivery and cesarean delivery rate. Results A total of 138 women were included in the study, 69 in each group. The mean time from MVI administration to any delivery showed no significant difference between the MVI-24 and MVI-10 groups (954 vs. 969 min, respectively; P = 0.679). The cesarean delivery rate was proportionally lower for the MVI-10 group [39.1% (27/69) vs. 24.6% (17/69); P = 0.10]. Conclusion The time from induction to delivery with MVI was similar when using standard criteria of up to 24 h of exposure vs. adjusted criteria of up to 10 h of exposure. Although the threshold for statistical significance for cesarean section was not attained, there is nonetheless a considerable difference between the MVI-24 and MVI-10 groups.

Clinical factors and ultrasound parameters to predict successful vaginal delivery following labour induction

Morbidity and complications are higher with caesarean delivery after labour induction. We aimed to evaluate which maternal/neonatal pregnancy characteristics and ultrasound parameters are useful in predicting successful vaginal delivery following labour induction. In this retrospective observational study, several maternal and foetal characteristics were studied in 197 primigravidae women at 38 or more gestational weeks before induction. Multivariate analysis showed that maternal age (odds ratio [OR] 0.907, 95% confidence intervals [CI] 0.826-0.995, p = .038), term body mass index (BMI; OR 0.909, 95% CI 0.828-0.997, p = .044), and foetal engagement (OR 3.295, 95% CI 1.232-8.810, p = .017) were independent predictors for a successful vaginal delivery in an induced labour. An older maternal age, high term BMI and un-engagement were associated with a failed labour induction.IMPACT STATEMENTWhat is already known on this subject? Labour induction is being used more frequently worldwide, but it is not always easy to predict those patients who will progress to a vaginal delivery and those who will require a caesarean section. Because caesarean sections are associated with a higher mortality and morbidity in patients who have undergone a labour induction, it is important to identify the factors predictive of successful vaginal delivery after labour induction.What do the results of this study add? Multivariate analysis showed that maternal age, term BMI, and foetal engagement were independent predictors for successful vaginal delivery in an induced labour.What are the implications of these findings for clinical practice and/or further research? We found that maternal age, term body mass index and foetal engagement were important variables to consider when predicting a successful labour induction. A comprehensive assessment of these variables should be done before inducing labour to limit any unnecessary mortality and morbidity associated with a failed induction. Women should be given accurate information regarding the risks of induction based on their individual characteristics.

Effects of induction of labor prior to post-term in low-risk pregnancies: a systematic review

OBJECTIVE

The objective of this review was to identify, assess and synthesize the best available evidence on the effects of induction prior to post-term on the mother and fetus. Maternal and fetal outcomes after routine labor induction in low-risk pregnancies at 41+0 to 41+6 gestational weeks (prior to post-term) were compared to routine labor induction at 42+0 to 42+6 gestational weeks (post-term).

INTRODUCTION

Induction of labor when a pregnancy exceeds 14 days past the estimated due date has long been used as an intervention to prevent adverse fetal and maternal outcomes. Over the last decade, clinical procedures have changed in many countries towards earlier induction. A shift towards earlier inductions may lead to 15-20% more inductions. Given the fact that induction as an intervention can cause harm to both mother and child, it is essential to ensure that the benefits of the change in clinical practice outweigh the harms.

INCLUSION CRITERIA

This review included studies with participants with expected low-risk deliveries, where both fetus and mother were considered healthy at inclusion and with no known risks besides the potential risk of the ongoing pregnancy. Included studies evaluated induction at 41+1-6 gestational weeks compared to 42+1-6 gestational weeks. Randomized control trials (n = 2), quasi-experimental trials (n = 2), and cohort studies (n = 3) were included. The primary outcomes of interest were cesarean section, instrumental vaginal delivery, low Apgar score (≤ 7/5 min.), and low pH (< 7.10). Secondary outcomes included additional indicators of fetal or maternal wellbeing related to prolonged pregnancy or induction.

METHODS

The following information sources were searched for published and unpublished studies: PubMed, CINAHL, Embase, Scopus, Swemed+, POPLINE; Cochrane, TRIP; Current Controlled Trials; Web of Science, and, for gray literature: MedNar; Google Scholar, ProQuest Nursing & Allied Health Source, and guidelines from the Royal College of Obstetricians and Gynaecologists, and American College of Obstetricians and Gynecologists, according to the published protocol. In addition, OpenGrey and guidelines from the National Institute for Health and Care Excellence, World Health Organization, and Society of Obstetricians and Gynaecologists of Canada were sought. Included papers were assessed by all three reviewers independently using the Joanna Briggs Institute System for the Unified Management, Assessment and Review of Information (JBI SUMARI). The standardized data extraction tool from JBI SUMARI was used. Data were pooled in a statistical meta-analysis model using RevMan 5, when the criteria for meta-analysis were met. Non-pooled results were presented separately.

RESULTS

Induction at 41+0-6 gestational weeks compared to 42+0-6 gestational weeks was found to be associated with an increased risk of overall cesarean section (relative risk [RR] = 1.11, 95% confidence interval [CI] 1.09-1.14), cesarean section due to failure to progress (RR = 1.43, 95% CI 1.01-2.01), chorioamnionitis (RR = 1.13, 95% CI 1.05-1.21), labor dystocia (RR = 1.29, 95% CI 1.22-1.37), precipitate labor (RR = 2.75, 95% CI 1.45-5.2), uterine rupture (RR = 1.97, 95% CI 1.54-2.52), pH < 7.10 (RR = 1.9, 95% CI 1.48-2.43), and a decreased risk of oligohydramnios (RR = 0.4, 95% CI 0.24-0.67) and meconium stained amniotic fluid (RR = 0.82, 95% CI 0.75-0.91). Data lacked statistical power to draw conclusions on perinatal death. No differences were seen for postpartum hemorrhage, shoulder dystocia, meconium aspiration, 5-minute Apgar score < 7, or admission to neonatal intensive care unit. A policy of awaiting spontaneous onset of labor until 42+0-6 gestational weeks showed, that approximately 70% went into spontaneous labor.

CONCLUSIONS

Induction prior to post-term was associated with few beneficial outcomes and several adverse outcomes. This draws attention to possible iatrogenic effects affecting large numbers of low-risk women in contemporary maternity care. According to the World Health Organization, expected benefits from a medical intervention must outweigh potential harms. Hence, our results do not support the widespread use of routine induction prior to post-term (41+0-6 gestational weeks).

Time-to-delivery and delivery outcomes comparing three methods of labor induction in 7551 nulliparous women: a population-based cohort study

OBJECTIVE

Determine time-to-delivery and mode-of-delivery in labor induction among women with unripe cervix.

STUDY DESIGN

7551 nulliparous women with singleton deliveries, ⩾37 weeks, Bishop Score ⩽6, induced with dinoprostone, misoprostol or transcervical single balloon catheter. Linear regression analysis was used to estimate mean time-to-delivery with β-estimates and 95% confidence intervals with adjustments. Multivariable logistic regression analysis was used to calculate odds of cesarean delivery, instrumental vaginal delivery, maternal and neonatal outcomes.

RESULTS

Adjusted mean time-to-delivery was 6.9 and 1.5 h shorter, respectively, when inducing labor with balloon catheter (mean 18.3 h, β -6.9, 95% confidence intervals; -7.6 to -6.3) or misoprostol (mean 23.7 h, β -1.5, 95% confidence intervals; -2.3 to -0.8) compared with dinoprostone (mean 25.2 h). There were no significant differences in adverse maternal or infant outcomes between induction methods.

CONCLUSIONS

Balloon catheter is the most effective induction method with respect to time-to-delivery in nulliparous women at term compared with prostaglandin methods.

Labor induction and cesarean delivery: A prospective cohort study of first births in Pennsylvania, USA

BACKGROUND

Mode of delivery at first childbirth largely determines mode of delivery at subsequent births, so it is particularly important to understand risk factors for cesarean delivery at first childbirth. In this study, we investigated risk factors for cesarean delivery among nulliparous women, with focus on the association between labor induction and cesarean delivery.

METHODS

A prospective cohort study of 2851 nulliparous women with singleton pregnancies who attempted vaginal delivery at hospitals in Pennsylvania, 2009-2011, was conducted. We used nested logistic regression models and multiple mediational analyses to investigate the role of three groups of variables in explaining the association between labor induction and unplanned cesarean delivery-the confounders of maternal characteristics and indications for induction, and the mediating (intrapartum) factors-including cervical dilatation, labor augmentation, epidural analgesia, dysfunctional labor, dystocia, fetal intolerance of labor, and maternal request of cesarean during labor.

RESULTS

More than a third of the women were induced (34.3%) and 24.8% underwent cesarean delivery. Induced women were more likely to deliver by cesarean (35.9%) than women in spontaneous labor (18.9%), unadjusted OR 2.35 (95% CI 1.97-2.79). The intrapartum factors significantly mediated the association between labor induction and cesarean delivery (explaining 76.7% of this association), particularly cervical dilatation <3 cm at hospital admission, fetal intolerance of labor, and dystocia. The indications for labor induction only explained 6.2%.

CONCLUSIONS

Increased risk of cesarean delivery after labor induction among nulliparous women is attributable mainly to lower cervical dilatation at hospital admission and higher rates of labor complications.

Temporal Trends in Late Preterm and Early Term Birth Rates in 6 High-Income Countries in North America and Europe and Association With Clinician-Initiated Obstetric Interventions

IMPORTANCE

Clinicians have been urged to delay the use of obstetric interventions (eg, labor induction, cesarean delivery) until 39 weeks or later in the absence of maternal or fetal indications for intervention.

OBJECTIVE

To describe recent trends in late preterm and early term birth rates in 6 high-income countries and assess association with use of clinician-initiated obstetric interventions.

DESIGN

Retrospective analysis of singleton live births from 2006 to the latest available year (ranging from 2010 to 2015) in Canada, Denmark, Finland, Norway, Sweden, and the United States.

EXPOSURES

Use of clinician-initiated obstetric intervention (either labor induction or prelabor cesarean delivery) during delivery.

MAIN OUTCOMES AND MEASURES

Annual country-specific late preterm (34-36 weeks) and early term (37-38 weeks) birth rates.

RESULTS

The study population included 2,415,432 Canadian births in 2006-2014 (4.8% late preterm; 25.3% early term); 305,947 Danish births in 2006-2010 (3.6% late preterm; 18.8% early term); 571,937 Finnish births in 2006-2015 (3.3% late preterm; 16.8% early term); 468,954 Norwegian births in 2006-2013 (3.8% late preterm; 17.2% early term); 737,754 Swedish births in 2006-2012 (3.6% late preterm; 18.7% early term); and 25,788,558 US births in 2006-2014 (6.0% late preterm; 26.9% early term). Late preterm birth rates decreased in Norway (3.9% to 3.5%) and the United States (6.8% to 5.7%). Early term birth rates decreased in Norway (17.6% to 16.8%), Sweden (19.4% to 18.5%), and the United States (30.2% to 24.4%). In the United States, early term birth rates decreased from 33.0% in 2006 to 21.1% in 2014 among births with clinician-initiated obstetric intervention, and from 29.7% in 2006 to 27.1% in 2014 among births without clinician-initiated obstetric intervention. Rates of clinician-initiated obstetric intervention increased among late preterm births in Canada (28.0% to 37.9%), Denmark (22.2% to 25.0%), and Finland (25.1% to 38.5%), and among early term births in Denmark (38.4% to 43.8%) and Finland (29.8% to 40.1%).

CONCLUSIONS AND RELEVANCE

Between 2006 and 2014, late preterm and early term birth rates decreased in the United States, and an association was observed between early term birth rates and decreasing clinician-initiated obstetric interventions. Late preterm births also decreased in Norway, and early term births decreased in Norway and Sweden. Clinician-initiated obstetric interventions increased in some countries but no association was found with rates of late preterm or early term birth.