Endometriosis and preterm birth: A Danish cohort study

Endometriosis-Related Genetic Factors and Their Role in Preterm Birth: A Two-Sample Mendelian Randomisation Study

OBJECTIVE

Endometriosis affects 10% of women worldwide and is linked to adverse pregnancy outcomes, including preterm birth. Recent epidemiological and genetic studies indicate that endometriosis may influence gestational duration and the likelihood of preterm birth. This study aimed to estimate the direct genetic causal effects of endometriosis on gestational duration and preterm birth using Mendelian randomisation (MR) analysis, leveraging genetic data from recent genome-wide association studies (GWASs).

DESIGN

A two-sample MR study.

SETTING

Summary statistics from published GWASs on European ancestry populations for endometriosis and gestational duration.

POPULATION OR SAMPLE

Instrumental variables for endometriosis were derived from a meta-analysis comprising 60 674 endometriosis cases and 701 926 controls.

METHODS

Genetic correlations and heritability estimates were calculated using linkage disequilibrium score regression. Two-sample MR with multiplicative random-effects inverse variance weighting assessed the primary objectives, supplemented by sensitivity analyses to validate MR assumptions.

MAIN OUTCOME MEASURES

Primary outcomes were gestational duration and preterm birth, sourced from the latest GWAS data.

RESULTS

LD score regression revealed no genetic correlation between endometriosis and either gestational duration or preterm birth. MR analysis showed no causal association between endometriosis and maternal effects on offspring gestational duration (β = 0.40, 95% CI: -0.39 to 1.19, p = 0.32) or preterm birth (OR = 0.94, 95% CI: 0.82-1.06, p = 0.36). Sensitivity analyses indicated pleiotropy but no violations of MR assumptions. Of the four loci overlapping between the gestational duration and endometriosis GWASs, three (EBF1, WNT4, and GDAP1) were identified as outliers using MR-Presso.

CONCLUSIONS

Contrary to observational studies, MR analyses found no direct causal link between endometriosis and gestational duration or preterm birth. Overlaps in genomic regions suggest that the relationship may be mediated through different biological pathways.

Association between infertility and cervical insufficiency in nulliparous women-the contribution of fertility treatment

BACKGROUND

Pregnancies conceived through assisted reproduction have been associated with increased risks of adverse pregnancy and delivery outcomes, including cervical insufficiency (CI). Despite CI being a significant cause of late miscarriage or preterm birth, there are minimal published data on the associations of infertility (with or without fertility treatment) with CI.

OBJECTIVE

To examine the associations between infertility-assisted reproduction and CI in nulliparous women.

STUDY DESIGN

This population-based case-control study used data from Swedish national health registers to extract 2662 cases of cervical insufficiency in singleton pregnancies of nulliparous women in the 21-year period (1992-2012). The reference group of 26,620 controls was extracted from the population of non-cases using simple random sampling.

RESULTS

On adjusting for maternal characteristics and medical history, infertility was associated with CI, overall (adjusted odds ratio [aOR] 1.91 [1.53, 2.39]) and in the subgroup of nonusers of fertility treatment, aOR 1.60 (1.21, 2.12), compared to women without infertility. Among women with infertility, pregnancies conceived with the aid of fertility treatment had higher risk of CI than naturally-conceived pregnancies, aOR 1.49 (1.05, 2.10). In the subgroup of women with infertility and no history of miscarriage, the use of fertility treatment was associated with CI, aOR 3.48 (2.02. 5.98). No association was found between fertility treatment and CI in the pregnancies of women with infertility and a history of miscarriage.

CONCLUSION

From this study, we conclude that CI in nulliparous women is associated with both infertility and its treatment. For infertile women, the risk of CI following fertility treatment was seen only in those with no history of miscarriage, providing crucial information for improving risk assessment and management strategies for preterm birth prevention in populations availing of fertility treatment.

Female reproductive disease, endometriosis: From inflammation to infertility

Despite the fact that endometriosis is a common gynecological disease that occurs in 10% of women of reproductive age, the pathogenesis and treatment strategy are not clear to date. Endometriosis patients are commonly characterized by adhesions in the pelvis or ovaries, which leads to prolonged inflammation in the abdominal cavity. To handle the chronic inflammation, changes of immune cells, including T cells, NK cells, and macrophage, are accompanied. Therefore, diverse cytokines and adhesions of the abdominal cavity lead to poor quality of ovarian follicles, inappropriate response to the hormone, and infertility. This review will guide researchers to summarize the molecular changes and identify new treatment strategies for endometriosis-mediated inflammation and pregnancy failure.

Untangling the independent effect of endometriosis, adenomyosis, and ART-related factors on maternal, placental, fetal, and neonatal adverse outcomes: results from a systematic review and meta-analysis

BACKGROUND

Women with endometriosis may constitute a group at a particularly increased risk of pregnancy-related complications. Furthermore, women selected for assisted reproductive technology (ART) are exposed to additional endocrinological and embryological factors that have been associated with adverse pregnancy outcomes.

OBJECTIVE AND RATIONALE

This study aimed to investigate the independent effect of endometriosis, adenomyosis, and various ART-related factors on adverse maternal, placental, fetal, and neonatal outcomes.

SEARCH METHODS

Published randomized controlled trials, cohort studies, and case-control studies were considered eligible. PubMed, MEDLINE, ClinicalTrials.gov, Embase, and Scopus were systematically searched up to 1 March 2024. This systematic review and meta-analysis was performed in line with the PRISMA and the MOOSE reporting guidelines. To thoroughly investigate the association between endometriosis/adenomyosis and adverse pregnancy outcomes, sub-analyses were conducted, whenever possible, according to: the method of conception (i.e. ART and non-ART conception), the endometriosis stage/phenotype, the coexistence of endometriosis and adenomyosis, any pre-pregnancy surgical treatment of endometriosis, and the form of adenomyosis. The odds ratio (OR) with 95% CI was used as effect measure. The quality of evidence was assessed using the GRADE approach.

OUTCOMES

We showed a higher risk of placenta previa in women with endometriosis compared to controls (34 studies, OR 2.84; 95% CI: 2.47, 3.26; I2 = 83%, moderate quality). The association was observed regardless of the method of conception and was particularly strong in the most severe forms of endometriosis (i.e. rASRM stage III-IV endometriosis and deep endometriosis (DE)) (OR 6.61; 95% CI: 2.08, 20.98; I2 = 66% and OR 14.54; 95% CI: 3.67, 57.67; I2 = 54%, respectively). We also showed an association, regardless of the method of conception, between endometriosis and: (i) preterm birth (PTB) (43 studies, OR 1.43; 95% CI: 1.32, 1.56; I2 = 89%, low quality) and (ii) cesarean section (29 studies, OR 1.52; 95% CI: 1.41, 1.63; I2 = 93%, low quality). The most severe forms of endometriosis were strongly associated with PTB. Two outcomes were associated with adenomyosis both in the main analysis and in the sub-analysis that included only ART pregnancies: (i) miscarriage (14 studies, OR 1.83; 95% CI: 1.53, 2.18; I2 = 72%, low quality) and (ii) pre-eclampsia (7 studies, OR 1.70; 95% CI: 1.16, 2.48; I2 = 77%, low quality). Regarding ART-related factors, the following associations were observed in the main analysis and confirmed in all sub-analyses conducted by pooling only risk estimates adjusted for covariates: (i) blastocyst stage embryo transfer (ET) and monozygotic twinning (28 studies, OR 2.05; 95% CI, 1.72, 2.45; I2 = 72%, low quality), (ii) frozen embryo transfer (FET) and (reduced risk of) small for gestational age (21 studies, OR 0.59; 95% CI, 0.57, 0.61; P < 0.00001; I2 = 17%, very low quality) and (increased risk of) large for gestational age (16 studies, OR 1.70; 95% CI, 1.60, 1.80; P < 0.00001; I2 = 55%, very low quality), (iii) artificial cycle (AC)-FET and pre-eclampsia (12 studies, OR 2.14; 95% CI: 1.91-2.39; I2 = 9%, low quality), PTB (21 studies, OR 1.24; 95% CI 1.15, 1.34; P < 0.0001; I2 = 50%, low quality), cesarean section (15 studies, OR 1.59; 95% CI 1.49, 1.70; P < 0.00001; I2 = 67%, very low quality) and post-partum hemorrhage (6 studies, OR 2.43; 95% CI 2.11, 2.81; P < 0.00001; I2 = 15%, very low quality).

WIDER IMPLICATIONS

Severe endometriosis (i.e. rASRM stage III-IV endometriosis, DE) constitutes a considerable risk factor for placenta previa and PTB. Herein, we recommend against superimposing on this condition other exposure factors that have a strong association with the same obstetric adverse outcome or with different outcomes which, if coexisting, could determine the onset of an ominous obstetric syndrome. Specifically, we strongly discourage the use of AC regimens for FET in ovulatory women with rASRM stage III-IV endometriosis or DE. We also recommend single ET at the blastocyst stage in this high-risk population.

REGISTRATION NUMBER

CRD42023401428.

Endometriosis, pregnancy and delivery complications: Evidence from the US nationwide inpatient sample 2005-2018

OBJECTIVE

Endometriosis is associated with higher risk of ectopic pregnancy, premature delivery, miscarriage, and other adverse maternal and fetal complications. This study aimed to assess the impact of endometriosis on maternal and fetal outcomes of singleton pregnancies in a large nationally representative database.

MATERIALS AND METHODS

This population-based, retrospective observational study extracted the data of women aged 20-49 years with singleton, spontaneously conceived pregnancies from the US Nationwide Inpatient Sample (NIS) database from 2005 to 2018. Included subjects were divided into those with ICD codes for endometriosis and those without (non-endometriosis group). Data of maternal and fetal outcomes were compared between groups and analyzed using regression analysis.

RESULTS

After excluding 17,124 women who conceived with assisted reproductive technology (ART), 162,155 women with multiple pregnancies, and 27,847 with abnormal trend weight values (TRENDWT), a total of 8,584,269 women were eligible. After propensity score matching (PMS) case-control 1:4 by age, 45,560 remained (9112 (0.1%) with endometriosis, 36,448 without) and were included in the analysis. The mean age of women before matching was 28.7 years, and 30.5 years after matching. The most common comorbidity was chronic pulmonary disease (3.6%). Smoking frequency was higher in women with endometriosis compared to those without (4.8% vs. 2.4%). Multivariable analysis adjusted for confounders revealed that endometriosis was associated with significantly higher risk of maternal complications, including pre-eclampsia and eclampsia, antepartum hemorrhage, placenta previa, Cesarean delivery, post-partum hemorrhage, disseminated intravascular coagulation (DIC), transfusion, hemoperitoneum, and hospital stays ≥6 days. For fetal outcomes, endometriosis was associated with higher risk of intrauterine growth restriction (IUGR), premature birth, birth defects and abortion.

CONCLUSION

Endometriosis during pregnancy is associated with maternal and fetal complications. Study findings may serve as a benchmark for expanding medical assistance for endometriosis-affected pregnant women.

Associations between endometriosis and adverse pregnancy and perinatal outcomes: a population-based cohort study

PURPOSE

To examine the association between endometriosis and adverse pregnancy and perinatal outcomes (preeclampsia, placenta previa, and preterm birth).

METHODS

A population-based retrospective cohort study was conducted among 468,778 eligible women who contributed 912,747 singleton livebirths between 1980 and 2015 in Western Australia (WA). We used probabilistically linked perinatal and hospital separation data from the WA data linkage system's Midwives Notification System and Hospital Morbidity Data Collection databases. We used a doubly robust estimator by combining the inverse probability weighting with the outcome regression model to estimate adjusted risk ratios (RR) and 95% confidence intervals (CIs).

RESULTS

There were 19,476 singleton livebirths among 8874 women diagnosed with endometriosis. Using a doubly robust estimator, we found pregnancies in women with endometriosis to be associated with an increased risk of preeclampsia with RR of 1.18, 95% CI 1.11-1.26, placenta previa (RR 1.59, 95% CI 1.42-1.79) and preterm birth (RR 1.45, 95% CI 1.37-1.54). The observed association persisted after stratified by the use of Medically Assisted Reproduction, with a slightly elevated risk among pregnancies conceived spontaneously.

CONCLUSIONS

In this large population-based cohort, endometriosis is associated with an increased risk of preeclampsia, placenta previa, and preterm birth, independent of the use of Medically Assisted Reproduction. This may help to enhance future obstetric care among this population.

Ovulation induction and subfertile untreated conception groups offer improved options for interpreting risks associated with ART

PURPOSE

To identify and characterise appropriate comparison groups for population studies of health outcomes in ART-conceived births: ovulation induction (OI), subfertile untreated and fertile natural conceptions. Our secondary objective was to examine whether known risks of pregnancy complications and adverse birth outcomes in ART births are elevated in comparison with subfertile (untreated and OI) conception groups.

METHODS

We linked State and Commonwealth datasets to identify all live and stillbirths (≥ 20 weeks) in Western Australia from 2003 to 2014 by method of conception. Demographic characteristics, maternal pre-existing conditions, adverse obstetric history and pregnancy complications were compared across conception groups. Generalised estimating equations were used to estimate adjusted risk ratios (aRRs) and 95% confidence intervals (CI) for pregnancy complications and birth outcomes in singletons.

RESULTS

We identified 9456 ART, 3870 OI, 11,484 subfertile untreated and 303,921 fertile naturally conceived deliveries. OI and subfertile untreated groups more closely resembled the ART group than the fertile group; however, some differences remained across parity, maternal age, pre-existing conditions and obstetric history. In multivariate analyses, ART singletons had greater risks of placental problems (e.g. placenta praevia aRR 2.42 (95% CI 1.82-3.20)) and adverse birth outcomes (e.g. preterm birth aRR 1.38 (95% CI 1.25-1.52)) than the subfertile untreated group, while OI singletons were more similar to the subfertile group with higher risk of preeclampsia and gestational diabetes.

CONCLUSION

OI and subfertile untreated conception groups offer improved options for interpreting health outcomes in ART births. Pregnancy complications (particularly placental disorders) and adverse outcomes at delivery are more common following ART.

Prevalence of Sex-Specific Cardiovascular Disease Risk Factors, Medical Risk, and Engagement in Health-Promoting Behaviours in Premenopausal Females

Background

Several sex-specific risk factors (SS-RFs) increase a women's risk for cardiovascular disease (CVD) but are often overlooked during risk assessment. The purpose of this study was to identify the prevalence of SS-RFs and assess CVD risk, knowledge, perceptions and behaviours in premenopausal Canadian women.

Methods

An online survey was distributed across Canada to premenopausal biological females (19-49 years of age). The survey gathered demographics, medical history, engagement in health-promoting behaviours, and knowledge and perceptions of CVD risk. CVD risk was calculated using medical risk and SS-RFs were tabulated from medical history.

Results

A total of 2559 participants (33 ± 8 years) completed the survey. The majority of our sample (82%) was classified as low medical risk. Of those classified as low risk, 35% had at least 1 SS-RF. Of high-risk individuals, 70% underestimated their risk, 21% of whom perceived themselves as low risk. Engagement in health behaviours was suboptimal. Knowledge of traditional CVD risk factors and prevention was relatively high; however, less than one-half were aware of SS-RFs such as early menopause (39.4%).

Conclusions

Considering both traditional and SS-RFs, 47% of premenopausal Canadian women may be at risk for developing CVD. Of those deemed low medical risk for developing CVD, more than one-third reported having at least 1 SS-RF. Canadian women have poor knowledge of the risks associated with SS-RFs, lack sufficient awareness of the need for prevention of CVD, and are not engaging in sufficient health-promoting behaviours to mitigate future CVD risk.

Adverse pregnancy outcomes associated with endometriosis in Ukraine: results a multicenter study

OBJECTIVE

Aim: To estimate pregnancy outcomes associated with endometriosis in Ukraine.

PATIENTS AND METHODS

Materials and Methods: We performed the multicentre prospective cohort study during the period from January 1st, 2019 to December 31st, 2021. The study included pregnant women aged ≥18 years hospitalized in 17 hospitals from 15 regions of Ukraine. Logistic regression analysis provided odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Results: Of the 27,558 women, 990 (3,6%) reported a diagnosis of endometriosis before pregnancy. In 990 deliveries, women with endometriosis had a higher risk of hypertension in pregnancy (OR 1.2, 95% CI 1.0-1.3), preeclampsia (OR 1.4, 95% CI 1.3-1.5), severe preeclampsia (OR 1.7, 95% CI 1.5-2.3), hemorrhage in pregnancy (OR 2.3, 95% CI 2.0-2.5), placental abruption (OR 2.0, 95% CI 1.7-2.3), placenta previa (OR 3.9, 95% CI 3.5-4.3), premature rupture of membranes (OR 1.7, 95% CI 1.5-1.8), and retained placenta (OR 3.1, 95% CI 1.4-6.6). The neonates had increased risks of preterm birth before 28 weeks (OR 3.1, 95% CI 2.7-3.6), birth before 34 weeks (OR 3.2, 95% CI 2.8-3.6), being small for gestational age (OR 1.5, 95% CI 1.4-1.6), being diagnosed with congenital malformations (OR 1.3, 95% CI 1.3-1.4), and neonatal death (OR 1.8, 95% CI 1.4-2.1).

CONCLUSION

Conclusions: Pregnant women with endometriosis are at elevated risk for serious and important adverse maternal, fetal and neonatal outcomes. The magnitude of these complications calls for more intensive antenatal care of pregnant women with endometriosis.

Association between pre-pregnancy body mass index and the risk of preterm birth: a mediating effect of hypertensive disorders of pregnancy

OBJECTIVE

We aim to explore the mediating effect of hypertensive disorders of pregnancy (HDP) on the relationship between pre-pregnancy body mass index (BMI) and the risk of preterm birth (PTB) in women with singleton live births.

METHODS

Demographic and clinical data of 3,249,159 women with singleton live births were extracted from the National Vital Statistics System (NVSS) database in this retrospective cohort study. The associations between pre-pregnancy BMI and HDP, HDP, and PTB, and pre-pregnancy BMI and PTB were evaluated using univariate and multivariate logistic regression analyses, with odds ratios (ORs) and 95% confidence intervals (CIs). Structural equation modeling (SEM) was used to explore the mediating effect of HDP on the relationship between pre-pregnancy BMI and PTB.

RESULTS

In total, 324,627 women (9.99%) had PTB. After adjustment for covariables, there were significant associations between pre-pregnancy BMI and HDP [OR = 2.07, 95% CI: 2.05-2.09)], HDP and PTB [OR = 2.54, 95% CI: (2.52-2.57)], and pre-pregnancy BMI and PTB [OR = 1.03, 95% CI: 1.02-1.03)]. The effect of pre-pregnancy BMI on PTB was significantly mediated by HDP with a mediation proportion of 63.62%, especially in women of different ages and having gestational diabetes mellitus (GDM) or not.

CONCLUSION

HDP may play a mediating role in the effect of pre-pregnancy BMI on PTB risk. Women preparing for pregnancy should pay close attention to BMI, and pregnant women should monitor and develop interventions for HDP to reduce the risk of PTB.