Association between endometriosis and pregnancy complications: A nationwide retrospective analysis (2000-2021)

OBJECTIVE: Endometriosis is a chronic gynaecological condition affecting reproductive-aged women. It has been associated with infertility and potential risks for adverse pregnancy outcomes, although population-level evidence remains limited. METHODS: This retrospective cohort study, including 147,950 pregnant women aged 20-45 years, used nationwide population-based data to compare the outcomes between women with (n = 11,400) and without (n = 136,550) endometriosis between 2000 and 2021. Baseline characteristics, comorbidities and pregnancy outcomes were compared between the groups. Multivariable regression analyses were performed to calculate adjusted relative risks (aRR) and 95 % confidence intervals (CI) for various pregnancy outcomes, and subgroup analyses were conducted by maternal age and infertility status. RESULTS: Among 147,950 pregnancies, women with endometriosis [mean ± standard deviation (SD) age 32.38 ± 4.51 years] had higher socio-economic status, more comorbidities, and more surgical history compared with women without endometriosis (mean ± SD age 30.06 ± 4.96 years). Women with endometriosis had increased risk of miscarriage (aRR 1.13, 95 % CI 1.03-1.24), preterm birth (aRR 1.31, 95 % CI 1.26-1.37), premature rupture of membranes (aRR 1.11, 95 % CI 1.06-1.16), placenta previa (aRR 1.63, 95 % CI 1.45-1.84), urinary tract infection (aRR 1.44, 95 % CI 1.31-1.59), and caesarean section (aRR 1.13, 95 % CI 1.11-1.16). Subgroup analysis revealed that risk of miscarriage was only higher in women aged 35-45 years and women without infertility. Risks of preterm birth, placenta previa and caesarean section were elevated across all subgroups, suggesting that endometriosis contributes independently to adverse pregnancy outcomes. CONCLUSIONS: Endometriosis is an independent risk factor for several pregnancy complications, supporting the need for tailored prenatal care and closer monitoring of affected women to improve maternal outcomes.