Which finding may be observed with first-trimester vaginal bleeding?

• A. Placental abruption
• B. Subchorionic hemorrhage
• C. Placenta previa
• D. Uterine fibroid

Answer: (B)

In early pregnancy, vaginal bleeding is often worked up with ultrasound to look for a hematoma at the implantation site. A subchorionic hemorrhage is a common finding in this setting. It’s a collection of blood between the chorion (the outer fetal membrane) and the endometrium, and on ultrasound it appears as a crescent-shaped area adjacent to the gestational sac that is fluid-filled (hypoechoic or anechoic) relative to surrounding tissue. The size and location of this hematoma help guide prognosis: small ones may resolve on their own and the pregnancy can continue normally, while larger ones can be associated with higher miscarriage risk and warrant serial imaging.

Placental abruption, placenta previa, and uterine fibroids have different typical contexts. Placental abruption usually occurs later in pregnancy and is often painful. Placenta previa involves placental tissue covering the cervical opening and generally presents with painless bleeding in the second or third trimester. Uterine fibroids can be seen on imaging and may affect pregnancy, but they aren’t a characteristic finding of first-trimester vaginal bleeding.