Risk Factors for Subchorionic Hematoma Affected Pregnancies in the Infertile Population

Abstract

OBJECTIVE: Unexplained recurrent pregnancy loss (uRPL) includes non-visualized pregnancy loss (NVPL, i.e. preclinical), visualized pregnancy loss (VPL, i.e. clinical), and Mixed (combination of VPL and NVPL) types of pregnancy losses. Our objective was to evaluate the association between the types of prior pregnancy losses and the outcome of the subsequent pregnancy in a cohort of uRPL women.DESIGN: A retrospective cohort study approved by ethics board (Approval number: H13-03306).MATERIALS AND METHODS: Women with uRPL who were referred to the RPL centre at British Columbia Women's Hospital (BCWH), between from January 1, 2011 to August 31, 2017 (n¼806) were included. Their clinical evaluations were completed according to the American Society of Reproductive Medicine (ASRM) guidelines. Data were collected using Research Electronic Data Capture (REDCap) data management platform. We compared women who had only non-visualized pregnancy losses (NVPL) with women who had only visualized pregnancy losses (VPL) and those with both types of uRPL with respect to demographic and clinical characteristics. We also compared pregnancy outcomes (successful pregnancy R10 weeks gestation vs. miscarriage at < 10 weeks gestation) among women with NVPL vs VPL groups. Logistic regression was used to adjust for potential confounders.RESULTS: There were 142 (18%) women with only NVPL, while 152 (19%) women had only VPL. The remaining 512 (63%) women had a mixture of both. In this cohort of 806 women, 679 had a subsequent pregnancy within 12 months, among these, 397 (58.4%) pregnancy reached R10 weeks' gestation, and 282 (41.5%) of pregnancies were miscarried (<10 week's gestation). Successful pregnancy reaching R10 weeks occurred in 45.4% (69/152) women with VPL, in 35.2% (50/142) women with NVPL, and in 54.3% (278/512) of women with both types (mixed group).Compared to women with VPL, women with NVPL were more likely to have prior primary pregnancy losses (AOR ¼ 2.26, 95% CI ¼ 1.32 -3.86), and prior history of therapeutic abortions (AOR ¼4.26 and 95% CI ¼ 1.65 -11.02). Among those who became pregnant, women with VPL were more likely to remain pregnant at or beyond 10 weeks' gestation (AOR ¼ 1.94, 95% CI ¼ 1.03 -3.66).CONCLUSIONS: Our study suggests that exclusive NVPLs are prevalent in women with uRPL. Women who had only NVPL were more likely to experience miscarriage at < 10 weeks' gestation compared with women with VPL in their subsequent pregnancy.