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

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.

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.

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, P<0.001) in the pregnant women with first-trimester IUH. There was no significant difference regard the prevalence of low birth weight (LBW; P=0.091), very LBW (P=0.370), or extremely LBW (P=0.600) between cases with IUH and without IUH, the cesarean section rate (68% vs. 81%, P=0.130), preterm delivery (16% vs. 16%, P>0.999), 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).

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.