Triploidy

(A) Sagittal view of a fetus at 13 weeks of gestation with triploidy. The fetal head is large compared with the body, indicating asymmetric growth restriction. Both nuchal translucency and the placenta appeared to be normal. Ventriculomegaly and a congenital heart defect were suspected. This constellation of findings is characteristic of digynic triploidy, where the extra complement of chromosomes is of maternal origin.
(B) Scan of a pregnancy at 11 weeks of gestation showing a placenta with numerous lucencies (dashed arrow). Most of the fetus is not visible in this image; however, the abdominal wall is seen in axial views, showing an omphalocele (arrow). The fetus also had a septated cystic hygroma. This constellation of findings is characteristic of diandric triploidy, where the extra haploid chromosomal complement is of paternal origin.