In first-trimester vaginal bleeding, which findings may be observed?

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

Answer: (A)

Early pregnancy vaginal bleeding often correlates with a subchorionic hemorrhage, a small collection of blood that forms between the uterine wall and the chorionic membranes at the implantation site. On ultrasound this appears as a crescent-shaped, fluid-filled area adjacent to the gestational sac. It results from detachment at the placental-implantation interface and is a common finding in the first trimester, sometimes associated with spotting or light bleeding. Most subchorionic hematomas resolve on their own, though larger ones can increase miscarriage risk.

Placental abruption usually occurs later in pregnancy and presents with painful bleeding and uterine tenderness, not typical in the first trimester. Placenta previa involves placenta over the cervical os and typically causes painless bleeding later in gestation. Uterine fibroids can cause bleeding, but they are not the characteristic early ultrasound finding associated with first-trimester vaginal bleeding.