Survival of preimplantation embryos in the uteri of mice induced to superovulate and subsequently ovariectomized.

The effect of ovariectomy-induced hormonal deprivation for 3, 5, 7 or 9 days on the capacity of the mouse uterus to maintain large numbers of blastocysts was studied. Both the percentage of pregnant females and the number of embryos per female decreased from 90% with 18.89 embryos per female after 3 days to 40%, with 4.63 embryos per female, after 9 days of hormonal deprivation. The capacity of embryos from superovulating donors to implant in pseudopregnant recipients was unimpaired during the first 5 days of hormonal deprivation but was significantly impaired after 7 days.