Trophoblast from anembryonic pregnancy has both a maternal and a paternal contribution to its genome

Androgenesis and gynogenesis are not causative in early pregnancy loss in humans

OBJECTIVE

Androgenetic and gynogenetic embryos in the mouse have been shown to fail early in development, exhibiting many features that are similar to those seen in early pregnancy loss in humans. Because androgenetic or gynogenetic abortuses contain the genetic complement from a single paternal or maternal genome, we used locus-specific minisatellite probes to determine individual genetic relationships and parentage from samples of parental blood and abortus tissue, to investigate whether androgenesis and gynogenesis contribute to the cause of early pregnancy loss.

STUDY DESIGN

We carried out prospective recruitment over 2 years of 145 patients admitted to a teaching hospital in Cambridge with ultrasonographic confirmation of early pregnancy failure.

RESULTS

Blood and products of conception suitable for complete analysis were obtained from 75 cases. Twenty-seven (56%) of the 48 samples that could be karyotyped had normal chromosome complements, with trisomy 16 the most frequent aberration (5/21). Both paternal and maternal genomic contributions to the abortuses were found in all cases investigated, irrespective of the karyotypes of the tissue. Germline mutations were detected in six of 42 (7.1% per gamete) hybridizations with lambda MS1 and in one of 15 (3.3% per gamete) with p lambda g3, which is higher than the rate estimate for the general population. No inappropriate paternity was detected.

CONCLUSION

Androgenesis and gynogenesis are unlikely to be causative in the cause of human early pregnancy loss, but germline mutations even in the presence of a normal karyotype could be influential.