A randomized controlled trial of extra-amniotic ethinyloestradiol in ripening the cervix at term

At the end of a pregnancy, some labors require artificial induction to complete the delivery process. However, successful induction is difficult to achieve if the cervix is not ripe (has not begun to efface and dilate) and such efforts to induce labor are associated with additional procedures and complications such as cesarean section and fetal infection. Previous research has explored methods of cervical ripening using the hormone ethinyloestradiol (estradiol) outside of the amniotic membranes. A study of first pregnancies which required induction despite an unripe cervix was designed to compare the effects of applying a gel to the cervix with a narrow tube (Foley catheter); in twenty-five patients the gel contained estradiol and in twenty-four patients it did not. The tube was inserted through the cervix and remained in place overnight before induction was attempted. There was no difference in the labor outcomes of the two groups, including the time period from induction to delivery and the rate of cesarean section. Researchers concluded that the cervix ripened due to the tube insertion which probably promotes the release of prostaglandins from fetal membranes. The low complication and failure rates, and the low cost associated with this method make it a desirable alternative to other methods to promote of cervical ripening.