The risk factors for miscarriage of viable intrauterine pregnancies in patients with heterotopic pregnancy after surgical intervention.

To summarize the clinical characteristics and explore the risk factors for miscarriage of a viable intrauterine pregnancy following surgical intervention in patients with heterotopic pregnancy (HP). A total of 106 women diagnosed with HP that underwent surgical intervention in the Women's Hospital School of Medicine Zhejiang University between January 2014 and December 2021 were included in this retrospective study. They were divided into a miscarriage group (n = 13) and an ongoing pregnancy group (n = 93) according to the outcomes of the HP within 2 weeks after surgery. Data regarding clinical characteristics, surgical conditions, postoperative recovery, and complications were collected and compared between the groups. Logistic multivariate analysis was performed to explore the risk factors for miscarriage in patients with HP within 2 weeks of surgical intervention. Among the 106 women with HP, 80 had tubal HP, 8 had cornual HP, and 18 had interstitial HP. Eighty-seven (82.1%) patients developed clinical symptoms that manifested primarily as abnormal vaginal bleeding and/or abdominal pain, whereas 19 (17.9%) patients had no clinical symptoms. The mean gestational age on the day of surgery was 7.2 weeks (inter-quartile range, 6.4-8.3). The miscarriage rate within 2 weeks of surgical intervention was 12.3% in patients with HP. Compared to the ongoing pregnancy group, the miscarriage group had a higher body mass index, earlier gestational age at treatment, and higher volume of hemoperitoneum (P < .05 for all). Logistic multivariate analysis indicated that the women with a hemoperitoneum volume > 200 mL had significantly higher risk of miscarriage after adjusting covariates [OR (odds ratio) = 5.285, 95% CI (confidence interval) (1.152-24.238), P < .05]. Hemoperitoneum volume was independently associated with miscarriage of viable intrauterine pregnancies in patients with HP within 2 weeks of surgical intervention.