Prenatal Sonographic Diagnosis of Type II Vasa Previa Associated with a Succenturiate Placental Lobe: A Case Report

Abstract

Background: Vasa previa is a rare but potentially life-threatening obstetric condition in which unprotected fetal vessels traverse the fetal membranes over or in close proximity to the internal cervical os. Prenatal diagnosis using grayscale ultrasonography and color Doppler allows identification of the aberrant fetal vessels before labor or membrane rupture and facilitates appropriate obstetric planning. Case Presentation: A 30-year-old fourth gravida, para 1 woman with no history of previous cesarean section presented at 34 weeks of gestation with intermittent per-vaginal spotting, occasional watery vaginal leakage, and lower abdominal pain. She had received irregular antenatal care. Ultrasonography demonstrated an anterior low-lying placenta with a posterior succenturiate placental lobe. Color Doppler imaging identified unprotected fetal vessels connecting the main placental mass and succenturiate lobe and traversing the internal cervical os, consistent with Type II vasa previa. The estimated fetal weight was 1,921 g. Iron-deficiency anemia was managed with transfusion of two units of packed red blood cells, and antenatal corticosteroids were administered. Follow-up ultrasonography at 35 weeks demonstrated oligohydramnios with an amniotic fluid index of 7.6 cm. At 37+ weeks, the patient developed heavy vaginal bleeding and underwent emergency lower-segment cesarean section. Intraoperatively, the main placenta and succenturiate lobe were identified with intact fetal vessels coursing between them. A male infant weighing 2.45 kg was delivered with Apgar scores of 6 and 8 at 1 and 5 minutes, respectively. The neonate required no neonatal intensive care admission, and both mother and infant recovered uneventfully. Conclusion: Careful sonographic assessment of placental morphology and fetal vessels, complemented by color Doppler imaging, enabled prenatal diagnosis of Type II vasa previa associated with a succenturiate placental lobe. Recognition of this potentially catastrophic condition allowed appropriate antenatal surveillance and obstetric preparedness, contributing to a favorable maternal and neonatal outcome. BJusg. vol. 26, no. 2, December 2025, Page: 107-112