Giving Misoprostol Before Vacuum Aspiration Lowers Risk of Complications

First published online:

Cervical preparation with misoprostol reduces a woman’s risk of complications from a first-trimester vacuum aspiration abortion, according to a multicountry, randomized controlled trial.1 Although women receiving misoprostol reported more abdominal pain, vaginal bleeding, nausea and other side effects before the abortion than those who received a placebo, they were less likely to report any complications after the procedure (relative risk, 0.7), notably incomplete abortion and incomplete abortion requiring uterine reevacuation. Overall, 2% of misoprostol recipients had a serious complication, compared with 3% of placebo recipients.

The researchers sought to assess whether cervical preparation with misoprostol for first-trimester abortion is associated with greater cervical dilation and reduced rates of complications. The trial was conducted from October 2002 to September 2005 at 14 hospitals in Armenia, China, Cuba, Hungary, India, Mongolia, Romania, Slovenia and Vietnam. Women requesting first-trimester pregnancy termination were eligible if they were in the first 84 days of pregnancy and were willing to return for follow-up; they were excluded if they had a known allergy to misoprostol, low hemoglobin levels, or a medical disorder that precluded routine vacuum aspiration or use of misoprostol or similar drugs.

Clinic staff recorded women’s demographic information and medical histories, and also measured hemoglobin concentrations. Length of pregnancy was determined by ultrasound. Three hours before their abortion, participants received either two 200-mg misoprostol tablets or two placebo tablets, administered vaginally; shortly before the procedure, the women were asked whether they had experienced any side effects from the drug. Study sites varied in the type of surgical equipment used (manual vs. electric aspiration pump; soft vs. metal tubes) and analgesic provided (paracervical block, general anesthesia, none). Women returned for follow-up visits 7–14 days after the abortion. The primary outcome of interest was any immediate or delayed complication following the procedure, including cervical tear, uterine perforation, incomplete abortion, incomplete abortion with uterine reevacuation, or pelvic inflammatory disease. P values were calculated for binary outcomes, and relative risks for continuous measures. Logistic regression and general linear models were used to test interactions.

A total of 4,972 women were randomized to either the misoprostol or the placebo group. Participants’ mean age was 27 years. Most women were married or cohabiting (70–71%), and 44% in each group had never given birth. The mean length of gestation was 7.9 weeks. For both groups, the average time between misoprostol administration and the abortion was 3.3 hours. During this time, higher proportions of women in the misoprostol group than in the placebo group reported abdominal pain (55% vs. 22%), vaginal bleeding (37% vs. 7%), nausea (7% vs. 4%), diarrhea (2% vs. 0%) and chills (3% vs. 1%); rates of vomiting, fever, dizziness, headache and rash were similar in the two groups (0–4%).

Cervical dilation before surgery was significantly greater in the misoprostol group than in the placebo group—7.0 vs. 5.9 mm, on average. As a result, the proportion of women who required additional dilation was smaller among misoprostol recipients than among those who received placebo (60% vs. 78%; risk ratio, 0.8); among women who required extra dilation, those who were in the misoprostol group needed less. The additional dilation in the misoprostol group allowed a wider suction tube to be used for uterine evacuation (means, 7.7 vs. 7.4 mm) and the vacuum aspiration procedure to be finished more quickly (3.6 vs. 3.9 minutes).

Before leaving the clinic on the day of the abortion, 71–75% of women in the two groups reported lower abdominal pain, 5% received analgesics and 0–1% reported diarrhea. Among the 98% of participants who returned for follow-up, a smaller proportion of women who had received misoprostol than of those who had received placebo reported one or more immediate or delayed complications from the abortion surgery (2% vs. 3%; risk ratio, 0.7). Few cases of cervical tearing or uterine perforation occurred, and rates did not differ between groups. However, compared with women in the placebo group, those in the misoprostol group were less likely to have had an incomplete abortion (1% vs. 2%; risk ratio, 0.4) or an incomplete abortion requiring uterine reevacuation (1% vs. 2%; risk ratio, 0.3). Analyses that stratified women by parity revealed that misoprostol reduced the risk of incomplete abortion (0.3) and incomplete abortion requiring uterine reevacuation (0.2) among parous women, but not among nulliparous women. There were no significant differences between the misoprostol and control groups in reports of pelvic inflammatory disease or other complications.

The researchers note that this is the first study with sufficient power to assess whether administering misoprostol before a first- trimester surgical abortion reduces the risk of complications. They acknowledge several limitations: The study may not have been fully blinded (because of small differences in the appearance of the misoprostol and placebo tablets); monitoring of the study sites was only occasional; and a misunderstanding in the method for determining the length of gestation led to enrollment of few women in the 12th week of pregnancy. However, the investigators note that their results are applicable to vacuum aspiration abortions up to 11 completed weeks of gestation. In a comment on the study, Templeton suggests that the range of surgical techniques used at participating centers may increase the generalizability of the study’s findings.2 Given that surgically induced abortion is the only procedure available in many parts of the world, Templeton underscores the importance of this study and suggests that "routine pharmaceutical dilation of the cervix should be recommended as an integral part of surgical abortion in all women."—L. Melhado


1. Meirik O et al., Complications of first-trimester abortion by vacuum aspiration after cervical preparation with and without misoprostol: a multicentre randomized trial, Lancet, 2012, 399(9828):1817–1824.

2. Templeton A, Misoprostol for all women seeking abortion? Lancet, 2012, 399(9828):1772–1773.