Coexisting Complete Hydatidiform Mole and a Viable Fetus: A Rare Twin Pregnancy Case with Favorable Neonatal Outcome

Introductıon: The purpose of this article is to report a rare case of twin pregnancy complicated by a complete hydatidiform mole with a live fetus and to review the clinical challenges associated with its management.
Case Presentation: A 21-year-old woman in her third pregnancy with a history of one previous birth and one miscarriage was referred to our tertiary clinic at 21 weeks of gestation with a suspected molar pregnancy. Ultrasonography revealed a dichorionic twin pregnancy consisting of a normal fetus and its anterior placenta, along with a posterior placental mass with a “bunch of grapes” appearance. Laboratory findings showed markedly elevated β-hCG levels and suppressed TSH values. Amniocentesis confirmed a normal fetal karyotype, but concurrent mole tissue analysis was initially inconclusive. The pregnancy was closely monitored with weekly β-hCG and ultrasound assessments. At 33+6 weeks, an emergency cesarean section was performed due to vaginal bleeding, and a male baby weighing 1750 g was born. Postnatal histopathology confirmed a complete hydatidiform mole in one placenta and a normal placenta in the other. Postpartum β-hCG levels gradually decreased, and no evidence of gestational trophoblastic neoplasia was observed on follow-up.
Conclusion: Twin pregnancy with a complete hydatidiform mole and a coexisting fetus is an extremely rare condition associated with significant maternal and fetal risks. Careful monitoring t may allow favorable outcomes in selected cases where continuation of pregnancy is chosen.

Keywords: Complete Hydatidiform Mole, Twin Pregnancy, Fetal Growth Restriction.