Risk factors for cervical insufficiency in women with polycystic ovarian syndrome：a cohort study

Abstract Background: To investigate the risk factors for cervical insufficiency (CI) in women with polycystic ovarian syndrome (PCOS). Methods: A total of 1553 women with PCOS were selected as study group. Additionally, 1553 women without PCOS were randomly selected to comprise the control group. ①The level of androstenedione, insulin resistance (IR) and antimullerian hormone (AMH) before pregnancy were collected and analysed. ② According to whether they accepted embryo transfer and different transfer cycles, whether they accepted hysteroscopy before pregnancy and the time period before pregnancy, the impact of clinical intervention measures on the occurrence of CI in the above PCOS cases was analysed. Main results: ①The incidence of CI in PCOS cases was 6.2%(97/1553), which was significantly higher than the 1.2%(19/1553) in the non-PCOS group (P<0.05). PCOS was a risk factor for CI (OR=4.467, 95%CI: 2.616~7.628). ②The level of androstenedione before pregnancy in PCOS cases with CI was significantly higher than that in PCOS cases without CI (15.98±7.95nmol/L vs. 13.32±6.67nmol/L, P=0.01). There was no significant difference in IR and AMH levels between the two groups. ③Embryo transfer was a risk factor for the occurrence of CI in PCOS cases (OR=3.415, 95%CI: 2.092~5.574). In embryo transfer cases, the incidence of CI in fresh cycle embryo transfer cases was 9.4%(30/382), which was higher than the 7.9%(15/159) in frozen embryo transfer cases, without statistically significant. In frozen cycle embryo transfer cases, the incidence of CI in natural cycle cases was 8.0%(2/25), which was higher than the 6.3%(11/166) in artificial cycle cases, with no statistically significant. ④The incidence of CI in women who underwent hysteroscopy within six months before pregnancy was 17.2%(5/29), which was significantly higher than the 6.0%(92/1524) in women who underwent hysteroscopy beyond six months before pregnancy or who did not undergo hysteroscopy (P=0.031). Conclusion: ① PCOS women receiving embryo transfer and hyperandrogenemia should be included in the population at high risk of CI after pregnancy, and the monitoring of cervical length should be strengthened during pregnancy. ② Frozen cycle embryo transfer and artificial cycle embryo transfer in frozen cycle embryo transfer might reduce the incidence of CI.