Association between subchorionic hematoma in the first trimester and outcomes of singleton pregnancies achieved through assisted reproductive technology: a systematic review and meta-analysis

Purpose To evaluate the association between first trimester (<= 12 weeks gestation) subchorionic hemorrhage (SCH), and maternal and neonatal outcomes in women who conceived with the help of assisted reproductive technique (ART). Methods PubMed, Embase, Web of Science, and Scopus databases were searched for observational studies that specifically focused on women who achieved pregnancy via ART and investigated the relationship between early pregnancy (within 12 weeks of gestation) SCH and maternal and neonatal outcomes. Only studies with singleton pregnancies and reporting data on the comparator group (women without SCH) were included. Primary outcomes of interest included incidences of early (within 20 weeks of gestation) pregnancy loss, preterm delivery, caesarean section, and live birth rates. Pooled effect sizes were reported as odds ratio (OR) with 95% confidence intervals (CI). Results Nine studies were included. All studies had a cohort design. In all studies, the primary assisted reproduction technique used was in-vitro fertilization (IVF). Compared to pregnancies without SCH, women with diagnosed early pregnancy SCH have a similar risk of preterm birth (< 37 weeks) (OR 1.01, 95% CI 0.83, 1.22), low birth weight (< 2500 g) (OR 1.01, 95% CI 0.59, 1.73) and fetal growth restriction (OR 1.57, 95% CI 0.62, 4.02). The gestational age (in weeks) (weighted mean difference (WMD) - 0.06, 95% CI - 0.18, 0.06) and the birth weight (in grams) (WMD - 16.5, 95% CI - 62.9, 29.8) were also similar in the two groups. The odds of early pregnancy loss (OR 1.39, 95% CI 0.97, 2.01), live birth (OR 0.77, 95% CI 0.55, 1.08) and caesarean delivery (OR 0.97, 95% CI 0.81, 1.16) were statistically similar in both groups. The risk of maternal adverse outcomes such as gestational diabetes (OR 0.98, 95% CI 0.74, 1.29), hypertensive disorder (OR 0.95, 95% CI 0.63, 1.43), premature rupture of membranes (PROM) (OR 1.36, 95% CI 0.90, 2.05) and placental abruption (OR 2.44, 95% CI 0.57, 10.5) was also similar in both the groups. There was no evidence of publication bias. Conclusion The findings suggest that SCH may not significantly increase the risk of adverse maternal and perinatal outcomes in pregnancies conceived through ART, particularly IVF.