Ultrasound at 14 weeks shows a normal-appearing fetus with an adjacent large vesicular placental mass. Karyotyping of the fetus would most likely show:

• A Triploidy, 69,XXY
• B Trisomy 21, 47,XY,+21
• C Monosomy X, 45,X
• D Normal biparental diploid karyotype ✓

Explanation

A complete mole coexisting with a normal fetus arises from dizygotic twinning: one conceptus is a normal biparental diploid pregnancy and the other an androgenetic complete mole. This contrasts with a partial mole, where the single conceptus itself is triploid (usually 69,XXY) with abnormal fetal tissue. Recognising the distinction matters because the coexisting-mole pregnancy carries a raised but manageable risk of persistent gestational trophoblastic disease.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.