Association between first-trimester subchorionic hematoma detected at 6-8 weeks of gestation and pregnancy outcomes after fresh embryo transfers: a propensity score-matching cohort study.

PURPOSE: This study aimed to investigate the association between first-trimester subchorionic hematoma (SCH) detected at 6-8 weeks of gestation after fresh embryo transfers and adverse pregnancy outcomes.

METHODS

We performed a retrospective cohort involving 3074 patients. All of them acquired singleton pregnancies after fresh embryo transfers in the first in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles. According to first-trimester ultrasound examinations at 6-8 weeks of gestation, we divided patients into SCH and non-SCH groups and compared their perinatal outcomes. Symptomatic patients with vaginal bleeding and asymptomatic patients were analyzed separately, and propensity score matching (PSM) and multivariable regression were adopted to control potential confounding factors.

RESULTS

The incidence of SCH was 17.1% in 3074 women, and vaginal bleeding occurred in 92 SCH patients and 215 control patients. In the asymptomatic cohort, 415 women with SCH and 807 women without SCH were finally included after PSM. No significant differences were observed in livebirth rate (91.3% vs 92.9%, P = 0.314), miscarriage rate (8.4% vs 6.7%, P = 0.267), and preterm birth rate (4.8% vs 5.7%, P = 0.519) between two groups. Secondary outcomes including gestational hypertension or preeclampsia, gestational diabetes mellitus (GDM), gestational age (GA) at delivery, mode of delivery, sex of newborns and birthweight of newborns were comparable. For symptomatic patients, both univariable and multivariable regression analysis showed no significant association between SCH and pregnancy outcomes. A subgroup analysis including patients with SCH illustrated the symptom of vaginal bleeding rather than hematoma size was associated with livebirth.

CONCLUSION

First-trimester SCH detected at 6-8 weeks of gestation was not associated with adverse pregnancy outcomes in singleton pregnancies after fresh embryo transfers. Vaginal bleeding was the risk factor of pregnancy loss for patients with SCH.