Mifepristone (RU 486) for cervical priming prior to surgically induced abortion in the late first trimester.

Mifepristone (RU 486; Roussell-Uclaf, Paris, France) is an antiprogesterone agent, which has been used successfully in combination with prostaglandin for early pregnancy medical abortion. Forty primigravidae were studied from 10-13 weeks of gestation. Women were randomly allocated to receive either placebo or a 600 mg single oral dose of Mifepristone 48 hours prior to vacuum aspiration under general anaesthesia. An objective mechanical method was used to assess the dilatation of the cervix at surgery. In 35% of the treated patients, there was no need for further dilatation prior to evacuation of the uterus. All patients in the placebo group required further dilatation (p less than 0.001). In those patients receiving Mifepristone who did require further dilatation, the initial dilatation of the cervix was significantly greater (p less than 0.01) and significantly less force was required to dilate the cervix to 9 mm (p less than 0.001). Perioperative blood loss was reduced. There were no serious complications or side effects. Mifepristone for cervical priming is safe and effective and has advantages over prostaglandins and hydrophilic cervical dilators.