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, 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).

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.