Risk of Abortion and Ectopic Pregnancy in Women with a History of Polycystic Ovary Syndrome: A Nationwide Population-Based Cohort Study.

The purpose of this retrospective cohort study was to ascertain the risk of abortion, ectopic pregnancy and hydatidiform mole development in women with polycystic ovary syndrome (PCOS) using data from Korea's National Health Insurance Service. The women aged 20-49 years who were diagnosed with PCOS between 1 January 2012 and 31 December 2020 were enrolled. The control group (non-PCOS group) was composed of women aged 20-49 years who visited medical institutions for health examinations during the same period. Women diagnosed with any cancer were excluded from both groups. Logistic regression analysis was used to evaluate the risks of abortion, ectopic pregnancy and hydatidiform mole in PCOS in the presence of certain pregnancy-related confounding factors. A total of 724,307 women were extracted, 169,998 women without PCOS and 44,714 women with PCOS were enrolled in the study. The PCOS group had a higher incidence of GDM and endometriosis. Abortions, ectopic pregnancies and hydatidiform moles were higher in the PCOS group than in the control group (abortion: 14.7% vs. 7.3%, < 0.001; ectopic pregnancy: 3.3% vs. 1.1%, < 0.001; hydatidiform mole: 0.2% vs. 0.1%, < 0.001). After adjusted logistic regression, PCOS was found to be a risk factor for abortion (RR = 1.473, 95% CI = 1.424-1.524; < 0.001) and ectopic pregnancy (RR = 1.845, 95% CI = 1.716-1.984, < 0.001) but not hydatidiform mole (RR = 1.225, 95% CI = 0.927-1.62, = 0.154). A history of PCOS itself might increase the risk of abortion and ectopic pregnancy. These findings could be useful in prenatal counseling and the management of patients with PCOS-associated pregnancies.