Incidental diagnosis of sad fetus syndrome in triplets.

An unusual presentation of gestational trophoblastic disease is twin molar pregnancy, rarest in triplets with differentials being partial/complete mole, placental mesenchymal dysplasia (PMD), placental cysts or chorioangioma each with different complications. Counselling to continue pregnancy depends on diagnosis. A 37-year-old G2P1L1, donor oocyte In vitro fertlisation (IVF) twin pregnancy was referred at 24 weeks with cystic areas in placenta. Probability of twin partial mole or PMD was assessed. The scan of fetuses showed normal growth, no structural anomalies. Biochemical markers showed high maternal beta human chorionic gonadotropin (β-hCG). Amniocentesis of molar fetus revealed normal karyotype. Likely diagnosis made as twin partial mole. The patient delivered by caesarean section at 28+2 weeks due to preterm labour. Twins, a male and a female baby, were delivered with three placentas, two normal and the third with molar changes and no fetal parts. Diagnosis was revised as triplet with partial mole, which was confirmed on histopathology. Serial monitoring of β-hCG became undetectable by eighth week. The male baby died on day 4. The mother and the female baby were discharged. © BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.