The effect of locally administered estrogens on the human cervix.

A randomized study to evaluate the effect of natural estrogens on the unripe uterine term cervix was conducted. One hundred and five term gravidas were studied, of whom 70 were treated with 180 mg 17 beta-estradiol or 250 mg estriol (treated women) and 35 were treated with gel only (control group). In all subjects the distented Foley catheter used for the instillation was left in situ. Twelve hours after the instillation there was no apparent difference in mean cervical progress between treated women and controls and the rather unexpected degree of cervical ripening is atributed to the intra-uterine balloon catheter. The procedure could not be shown to have any untoward effect on the mother or the fetus.