Adverse effects of gonadotrophin treatment on pre- and postimplantation development in mice.

The effect of gonadotrophins on pre- and postimplantation development in mice was investigated by superovulating C57BL/6J/Bom females with pregnant mares' serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG) or by inducing ovulation with hCG. In both hormone treated groups, the proportion of abnormal preimplantation embryos increased compared with naturally ovulating animals. Postimplantation mortality increased and the mean number of live fetuses per pregnant mouse decreased in superovulated and hCG-treated mice compared with controls. Embryonic growth was highly retarded. Mean weight of live fetuses in superovulated and hCG-treated mice was reduced and skeletal examination revealed developmental retardation. In conclusion, superovulation as well as induction of ovulation adversely affected embryonic and fetal development.