Clinical Significance of Subchorionic and Retroplacental Hematomas Detected in the First Trimester of Pregnancy

OBJECTIVE: To evaluate the long-term clinical significance of intrauterine hematomas detected in the first trimester of pregnancy in a general obstetric population. METHODS: A prospective study was designed to compare perinatal outcomes in 187 pregnant women with intrauter-ine hematomas and 6488 controls in whom hematomas were not detected at first-trimester ultrasonographic examination. RESULTS: The incidence of intrauterine hematoma in the first trimester in a general obstetric population was 3.1%. A retroplacental position of the hematoma was significantly correlated with an increased risk for adverse maternal and neonatal complications. The presence or absence of symp-toms of threatened abortion did not affect these outcomes. The rates of operative vaginal delivery (relative risk [RR] 1.9; confidence interval [CI] 1.1, 3.2) and cesarean delivery (RR 1.4; CI 1.1, 1.8), as well as the rates of pregnancy-induced hypertension (RR 2.1; CI 1.5, 2.9) and preeclamp-sia (RR 4.0; CI 2.4, 6.7), were significantly greater in the hematoma group. Placental abruption (RR 5.6; CI 2.8, 11.1) and placental separation abnormalities (RR 3.2; CI 2.2, 4.7) were also significantly more frequent in the hema-toma group. Perinatal complications, including the rate of preterm delivery (RR 2.3; CI 1.6, 3.2), fetal growth restric