Complications of pregnancy in mice exposed prenatally to DES.

Women exposed prenatally to diethylstilbestrol (DES) develop a variety of reproductive tract anomalies. Most of these anomalies have been replicated in strain CD-1 mice after similar DES exposure. Recently, impaired reproductive performance in DES-exposed women has been reported. To see whether the mouse model also replicates this defect, a study of reproduction was performed. Pregnant CD-1 mice were injected with DES and their female offspring were raised to breeding age. The latter were then exposed continuously to untreated males for a maximum of 4 months. Among 74 mated mice, 34 became pregnant and 11 of these pregnancies ended in abortion or stillbirth. Other anomalies encountered were: two fetuses with compressed heads, one of which seemed blocked from delivery by a vaginal adenocarcinoma; two uterine tumors, one of which was a teratocarcinoma; two teratomas located in uterine lumina; and two uteri containing placentas without embryos. Since the frequency of successful pregnancies in the DES-exposed mice was reduced below control levels to a degree similar to that reported for DES-exposed women, the validity of the mouse model has been confirmed for this characteristic.