Effects of triploidy on early human development.

OBJECTIVE

The morphologic features of 18 triploid embryos are described.

METHOD: Embryoscopic examination of the embryo in cases of missed abortion before instrumental evacuation from the uterus. Cytogenetic and histologic analysis of the chorionic villi.

RESULTS

Seventeen out of 18 triploid embryos showed structural defects on embryoscopic examination. The most common defects were facial anomalies (n = 15), limb abnormalities (n = 13), microcephaly (n = 11) and neural tube defects (n = 10); 3 embryos were classified as growth disorganized. Placenta of 12 grossly abnormal embryos was diagnosed as partial hydatidiform moles on histological examination.

CONCLUSIONS

The grossly abnormal development of the embryo observed in 12 partial hydatidiform moles indicate that, in aborted triploid embryos, the presence of two paternal genomes might have both placental and embryonic consequences. Transcervical embryoscopy in cases of missed abortion can serve as a central component in additional studies using molecular determination of parental origin of triploidy to establish the true proportion of diandric triploidy among grossly abnormal triploid embryos.