Associations between the size and duration of asymptomatic subchorionic hematoma and pregnancy outcomes in women with singleton pregnancies

BACKGROUND: The purpose of this study was to investigate the relationship between the size and duration of asymptomatic subchorionic hematoma and pregnancy outcomes in women with singleton pregnancies. METHODS: This was a retrospective study that enrolled 701 singleton pregnant women who were diagnosed with asymptomatic subchorionic hematoma by ultrasound at 5–10 gestational weeks. The control group recruited 640 normal pregnant women without subchorionic hematoma who were matched with subchorionic hematoma group on baseline characteristics. The pregnancy outcomes were compared between the two groups, and the associations of the size and duration of subchorionic hematoma with pregnancy outcomes were analyzed by logistic regression model. RESULTS: Compared with the normal pregnancy group, the incidence of, gestational diabetes mellitus, gestational thrombocytopenia, placenta adhesion, fetal growth restriction, macrosomia in subchorionic hematoma group were higher (all P < 0.05). After adjusting for confounding factors, the hematoma size was positively associated with the occurrence of gestational hypothyroidism (adjusted OR[95%CI]: 1.029[1.004–1.054]), intrahepatic cholestasis of pregnancy (adjusted OR[95%CI]: 1.095[1.047–1.146]), term premature rupture of membranes (adjusted OR[95%CI]: 1.044[1.005–1.085]), hypertensive disorders of pregnancy (adjusted OR[95%CI]: 1.030[1.0004-1.060]), gestational thrombocytopenia (adjusted OR[95%CI]: 1.078 [1.045–1.113]), placenta adhesion (adjusted OR[95%CI]: 1.054 [1.027–1.082]), and the duration of hematoma was positively associated with the incidence of term premature rupture of membranes (adjusted OR[95%CI]: 1.070[1.027–1.115]), gestational diabetes mellitus (adjusted OR[95%CI]: 1.938 [1.886–1.993]) and fetal growth restriction (adjusted OR[95%CI]: 1.194 [1.124–1.268]). CONCLUSIONS: The presence, size and duration of a first-trimester asymptomatic subchorionic hematoma may be associated with adverse pregnancy outcomes at later gestations such as term premature rupture of membranes and fetal growth restriction.