The impact of first-trimester intrauterine hematoma on adverse perinatal outcomes

Purpose The aim of this study was to evaluate whether the presence of an intrauterine hematoma (IUH) on an early pregnancy ultrasound scan showing a live fetus was related to adverse perinatal outcomes. Methods We performed a retrospective cohort study to evaluate pregnant women who underwent an ultrasound examination in early pregnancy, between 6 weeks 0 days and 10 weeks 6 days. We compared the perinatal outcomes between women with and without firsttrimester IUH using the Mann-Whitney and Fisher exact tests. Furthermore, we performed a stepwise regression analysis to identify possible predictors of miscarriage among maternal characteristics, ultrasound parameters, and IUH. Results During the study period, data from 783 pregnancies were included, and the incidence of IUH was 4.5% (35 of 783). We observed a higher proportion of miscarriage following the scan (28.6% vs. 10%, P=0.003) and a larger yolk sac diameter during the scan (4.8 mm vs. 3.8 mm, P0.999), or the incidence of first-trimester vaginal bleeding (31% vs. 20%, P=0.130). Moreover, heart rate (HR) was the only variable that predicted miscarriage with statistical significance (P=0.017). Conclusion Women with first-trimester IUH had a higher risk of miscarriage after the ultrasound scan. HR was the only variable that predicted miscarriage with statistical significance