P31.11: Complete hydatidiform mole and normal live birth: placental mosaicism or twin with CHM?

Abstract

Introduction: survival of a normal fetus to term in the presence of hydatidiform mole remains an extremely uncommon occurrence. Prenatal diagnosis is possible by ultrasonography showing molar invasion of the normal placenta without clear margin. Antenatal detection of mole co existing with a viable fetus should warrant genetic analysis and search for gross malformation of the fetus. Case report: we report a rare case exhibiting molar pregnancy and a coexisting normal fetus. A 29 year, primigravida had an episode of vaginal bleeding at 18 weeks which suggested avascular lower placenta with multiple cystic area measuring 12 × 5 × 9 cm with normal fetus. She had two weekly growth scan and Doppler as diagnosis was not clear. It was thought to be multiple placental lakes. Growth and Doppler remains normal and had term SVD. Placenta was sent for histopathology which suggested normal placenta with an area of complete hydatidiform mole. It was difficult to differentiate from mosaic CHM, twin with normal co-twin and CHM. Discussion: coexistent live fetus and molar placenta has never been reported. Complications including pre-eclampsia, hyperthyroidism, vaginal bleeding, persistent gestational trophoblastic disease, preterm labour, miscarriage and anaemia increases. Several factors may influence the outcome in partial mole such as karyotype of the fetus, size of the molar placenta, the speed of molar degeneration and fetal anaemia.