Trisomy 13 appearing as a mimic of a triploid partial mole

Trisomy 13 is a chromosomal abnormality that has been reported in approximately 1 per 20,000 live births. The phenotypic features of trisomy 13 include cardiac defects, cleft lip and palate, and cranial and central nervous system anomalies. Fetal triploidy has been estimated to occur in 1 per 10,000 live births, and it is the additional paternal haploid chromosomes that are associated with the development of the partial hydatidiform mole. Fetal anomalies described in triploid fetuses include intrauterine growth restriction, craniofacial anomalies, and syndactyly, among many others. The association of preeclampsia with a partial hydatidiform mole is well known and estimated to occur in 35% of triploid pregnancies. We present a case of trisomy 13 in association with preeclampsia and abnormal ultrasonographic findings that initially suggested fetal triploidy and a partial hydatidiform mole.