Endometriosis and preterm birth: A Danish cohort study

Abstract

Introduction Emerging evidence shows that women with endometriosis face a higher risk of preterm birth. However, the pathways are unclear. The objective of this study is to further investigate at different gestational ages the association between endometriosis and different pathways of preterm birth including, medically indicated preterm birth, premature pre‐labor rupture of membranes (PPROM), and spontaneous labor contractions. Material and methods In this population‐based cohort study we linked singleton pregnancies from the Aarhus Birth Cohort to the Danish National Patient Registry, the Danish Medical Birth Registry, the Danish National Pathology Registry and Data Bank, and the Danish in vitro fertilization registry to gather information on endometriosis status, outcomes and maternal characteristics. We investigated preterm birth before 37 completed weeks of gestation and very preterm birth before 32 completed weeks of gestation. We explored different pathways including medically indicated preterm birth defined as induction of labor with intact membranes and no prior labor contractions, PPROM defined as rupture of membranes, and spontaneous labor contractions defined as contractions with intact membranes resulting in labor. Results We found that women with endometriosis had an increased risk of preterm birth before 37 gestational weeks overall (adjusted hazard rate [aHR] 1.6, 95% confidence interval [CI] 1.3–1.9) and very preterm birth before 32 gestational weeks (aHR 1.8, 95% CI 1.1–2.9) compared with women without endometriosis. Medically indicated preterm birth was more prominent in women with endometriosis in deliveries before 37 gestational weeks (aHR 2.4, 95% CI 1.8–3.2) whereas spontaneous labor contractions were more common before 32 gestational weeks (aHR 2.2, 95% CI 1.1–4.5) in women with endometriosis compared with women without endometriosis. Further, in the analyses restricted to women with a histologically verified diagnosis of endometriosis, the results were strengthened overall and showed that women with endometriosis had an increased risk of PPROM before 32 gestational weeks (aHR 3.49, 95% CI1.36–8.98). Conclusions Endometriosis was associated with both preterm and very preterm birth; however, apparently through different pathways. Women with endometriosis were more prone to have medically indicated preterm births before 37 gestational weeks and spontaneous preterm births before 32 gestational weeks compared with women without endometriosis.

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

“…Since these conditions are associated with infertility, the prevalence is likely reduced in women giving birth. Endometriosis, for example, is thought to affect 10% of reproductive age women [ 26 ] and was ascertained in hospital data for only 3% of deliveries in our cohort and 2.4% of a recent Danish singleton cohort (1989–2013) [ 32 ]. PCOS is reported to occur in 7–14% of reproductive age women and was diagnosed in only 0.6% of our cohort compared to 1.3% of a Swedish cohort 2005–2014 [ 33 ] where data were also available on outpatient specialist care (both public and private).…”

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

“… 12 , 48 , 49 The quantification of cumulative risk is further complicated by the increased odds of developing a subsequent SS-RF when one already exists for an individual. For example, endometriosis has been linked to greater odds of having an APO, 50 , 51 , 52 , 53 PCOS, 54 early menopause 39 , 55 associated with early age of menarche, 56 , 57 and breast cancer. 58 , 59 Challenges aside, effective screening involves early identification of risk factors that can be addressed with recommended prevention and or treatment guidelines, with the ultimate goal of improving health outcomes.…”

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

“…We included women diagnosed before and after pregnancy in the primary analysis because recent studies documented a diagnosis delay of 8-12 years [4][5][6]. This approach has been adopted by other recent studies [15,19].…”

“…The association between endometriosis and adverse pregnancy outcomes has drawn more attention in recent years with fairly consistent evidence of increased risks for caesarean section, preterm birth, and stillbirth [11,12]. However, the link with gestational diabetes, preeclampsia, or intrauterine growth restriction remains less clear due to heterogeneity in study designs and methodologies used in previous studies [13][14][15][16][17][18][19][20][21]. In epidemiology, it remains challenging to study the direct impact of endometriosis on pregnancy outcomes, and underlying mechanisms are not well understood.…”