Prenatal Diagnosis of Twin Pregnancies with Complete Hydatidiform Mole and Coexistent Normal Fetus: A Series of 13 Cases

Aim: The study aimed to describe prenatal diagnosis and the outcome of complete hydatidiform mole and coexistent normal fetus (CHMCF). Methods: This was a retrospective case series of 13 patients with CHMCF. Prenatal diagnosis, outcome and development of gestational trophoblastic neoplasia (GTN) were reviewed. Results: Ultrasound diagnosis was carried out in 12 of 13 cases at 17 ± 2.7 weeks of gestation (mean ± SD). Six patients showed abnormalities suggestive of subchorionic hematoma on first trimester ultrasonography (US). Prenatal invasive procedures were performed in 8 of 13 cases (62%). Two women decided to terminate their pregnancies. Four ended in late miscarriages (36%, 4 of 11) between 13 and 21 weeks, and early neonatal death occurred in 1 case (9%, 1 of 11); 5 women delivered a live baby with a mean gestational age of 31 weeks (range 26-37 weeks) with an overall neonatal survival of 45% (5 of 11). GTN occurred in 31% of cases (4 of 13). Conclusions: The first trimester US features of CHMCF are not well-documented. Our series showed that abnormalities of CHMCF could be misdiagnosed as subchorionic hematoma in the early first trimester. When CHMCF is confirmed by expert US, prenatal invasive procedures should be carefully evaluated depending on the associated US findings and exhaustive counseling should be performed.