The effect of cervical encerclage on plasma prostaglandin concentrations during early human pregnancy.

In women having either cervical encerclage under general anaesthesia or a vaginal examination in the early second trimester of pregnancy, peripheral plasma levels of 13,14-dihydro-15-keto prostaglandin F (PGFM) were measured before and after each procedure. A significant rise in circulating levels of PGFM was found within minutes of completing cervical encerclage but not after vaginal examination or induction of general anaesthesia.