Establishment of the need for oestrogen during implantation in non-human primates

Deprivation of oestrogen during post-ovulatory mated cycles in proven fertile female bonnet monkeys by tamoxifen, aromatase inhibitor or oestrogen antiserum resulted in inhibition of pregnancy establishment in all three groups of animals. However, more than 85% of the animals became pregnant within three exposures to proven fertile males in the control group. These results suggest the requirement for oestrogen in pregnancy establishment in primates. Based on this conclusion, it is suggested that use of a suitable and potent anti-oestrogenic compound can be exploited as an alternative approach to contraception.