Prominent decidual vasculature overlying the internal cervical os: an entity potentially leading to acute life-threatening antepartum hemorrhage.

We report a new entity of prominent decidual vasculature overlying the internal cervical os which caused life-threatening antepartum uterine bleeding in a rhesus (Rh) D-negative patient at 32(+5) weeks' gestation. Cesarean hysterectomy was performed because of diffuse placenta increta. Early hospitalization, advanced preparation for emergency cesarean section, and timely blood transfusion, including 2L of RhD-positive packed red blood cells, aided in saving the lives of the patient and her baby. To the best of our knowledge, the ultrasound findings of this condition have never been reported. This condition could be considered as an independent sign for identification of a patient who is potentially at risk of acute massive antepartum hemorrhage. It deserves early accurate diagnosis by obstetricians using transvaginal sonography with color Doppler analysis.