The Vasa previa type II (bilobed/succenturiate lobe placenta) is distinguished from type I by which characteristic?

• A Type II vessels pass between the lobes of a succenturiate/bilobed placenta rather than at the placental edge ✓
• B Type II involves a velamentous cord insertion unlike type I which has marginal cord insertion
• C Type II has higher perinatal mortality than type I due to deeper placentation
• D Type II vasa previa is associated with prior uterine surgery while type I is not

Explanation

Vasa previa Type I occurs when fetal vessels traverse the lower uterine segment due to velamentous cord insertion. Type II occurs when fetal vessels connect the main placenta to an accessory (succenturiate) lobe, and these vessels cross the cervical os. Both types carry equally high fetal mortality if vessels rupture at membrane rupture (>50% fetal mortality in undiagnosed cases due to fetal exsanguination). Diagnosis by transvaginal color Doppler in second trimester allows elective cesarean at 34-36 weeks. Velamentous insertion is the defining feature of type I, while type II relates to multi-lobed placenta.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.