Complete hydatidiform mole coexisting with a viable pregnancy as twins after intracytoplasmic sperm injection: a case report.

Twin pregnancies with 1 healthy fetus and 1 hydatidiform mole are extremely rare events, occurring in 1:20,000-100,000 twin pregnancies.A 32-year-old, nulliparous woman underwent assisted reproduction due to male factor infertility. At 15 weeks' gestation a complete hydatidiform mole coexisting with a viable pregnancy was diagnosed. The couple decided to maintain the pregnancy following detailed counseling regarding the risks and benefits. At 26 weeks' gestation the patient prematurely delivered a 720-g fetus who did not survive due to extreme prematurity. The patient also delivered the products of the molar pregnancy.In the event ofa twin pregnancy with 1 viable fetus and 1 molar, continuing the pregnancy may be considered as far as the mother is fully informed, not only regarding the complications that may arise but also regarding the chances of delivering a healthy infant.