Prenatal diagnosis of an intertwin membrane hematoma.

We report a case of a 26-year-old woman, gravida 2, para 1, with a dichorionic diamniotic twin pregnancy at 33 weeks of gestation with a 1-day history of mild vaginal bleeding and irregular uterine activity. Ultrasonography showed 18 x 15 x 3-cm-sized complex hypoechoic mass located in the dividing intertwin membrane. Based on this finding, the diagnosis of an intertwin membrane hematoma was made. This unusual sonographic diagnosis was confirmed during the cesarean section. In the case of dichorionic twin pregnancy, partial placental abruption can lead to a subclinical intertwin membrane hematoma.