New adverse obstetrics outcomes associated with endometriosis: a retrospective cohort study

Purpose: The main aim of this study was to evaluate the incidence of endometriosis and intrahepatic cholestasis (ICP) and induction of labor in pregnant women with endometriosis compared with women without endometriosis. The secondary aim was to confirm increased incidence of already known endometriosis-related pregnancy complications in these patients.

Methods: This is a retrospective cohort study performed at a tertiary hospital between January 2009 and December 2014 to compare obstetrics outcome between women with endometriosis and women without endometriosis. Pregnant patients with endometriosis were included in the study group. Patients were divided in the following subgroups: patients with deep infiltrating endometriosis (DIE subgroup) and patients without deep infiltrating endometriosis (non-DIE subgroup); patients with singleton pregnancy and spontaneous conception (subgroup A) and patients with multiple pregnancy and/or patients who underwent assisted reproductive technology (subgroup B). To form a control group, for each patient with endometriosis, two patients without endometriosis were selected as the control group by means of matched sample.

Results: The study population included 262 pregnant women with endometriosis and 524 controls. Patients of the study population had significantly increased risks of placenta praevia (p < 0.05), ICP (p < 0.01), induction of labor (p < 0.01) and preterm birth (p < 0.01). DIE patients had a significantly higher percentage only of preterm birth (p < 0.01), while in non-DIE group all complications had a higher incidence except for placenta praevia, which did not differ with control. Subgroup A had a statistically higher incidence of placenta praevia (p < 0.01), ICP (p < 0.01), induction of labor (p < 0.01) and preterm birth (p < 0.01) compared to its control subgroup. There was no difference in distribution of pregnancy complications between subgroup B and control subgroup.

Conclusions: Our results showed for the first time that women with endometriosis are at higher risk of developing ICP and experiencing an induced labor. Further studies are warranted to clarify whether the history of endometriosis might be taken into account in the antenatal care of these patients.