Use of Misoprostol to Treat Incomplete Abortion Should Be Limited To the First 12 Weeks of Pregnancy

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The use of misoprostol for incomplete abortion should be limited to pregnancies of up to 12 weeks, even if a relatively high dose is used, according to a study conducted in Benin.1 Over a five-year period, the percentage of incomplete abortion cases that were successfully treated with 800 mcg of misoprostol (i.e., they did not require manual vacuum aspiration to complete uterine evacuation) was 99% among women with pregnancies of 12 or fewer weeks, compared with 26% among women with pregnancies of 13–14 weeks and 28% among women with pregnancies of 15–18 weeks. In addition, the risk of adverse effects from misoprostol was significantly lower during the first 12 weeks of pregnancy than later in pregnancy.

In 2006, in an effort to reduce the country’s high maternal mortality ratio, the government of Benin implemented a policy to improve postabortion care for women who had had spontaneous or induced abortions. Sharp curettage was replaced by manual vacuum aspiration, and in 2008, the use of misoprostol was adopted. Although a substantial body of literature has documented the effectiveness of misoprostol to treat early incomplete abortion, no studies have examined misoprostol’s success rate at higher doses to treat incomplete abortions after 12 weeks’ gestation. To fill this gap, and to provide a picture of misoprostol use in a low-resource environment with a high demand for postabortion care, researchers conducted a descriptive, prospective study between 2008 and 2012 at three maternity hospitals in Cotonou.

Women were eligible for the study if they were admitted to one of the hospitals with a diagnosis of incomplete abortion (determined by ultrasonography and clinical examination), did not have severe complications requiring immediate treatment and had an estimated gestational age of up to 18 weeks. Those who had stable blood circulation and uterine contents of less than 20 mm were given the option of medical treatment, manual vacuum aspiration, sharp curettage or no treatment, and were counseled about possible adverse effects and the importance of follow-up visits. Women choosing medical treatment were given 800 mcg misoprostol sublingually; follow-up visits were scheduled for three days later (to assess progress) and 15 days later (to perform ultrasound). At the latter visit, the treatment was considered successful if the uterus was empty or if the uterine contents were minimal and the woman was asymptomatic. The treatment was considered a failure if the woman was still bleeding or cramping and the uterus was not empty; at this time, manual vacuum aspiration was performed unless the woman was stable and opted for a second 800 mcg dose of misoprostol. If she opted for misoprostol, the woman was examined again 10–15 days later; if the uterus was still not empty, manual vacuum aspiration was performed. Data were collected on choice of treatment, gestational age at abortion, adverse effects, ultrasound results and need for vacuum aspiration after misoprostol. Chi-square testing was used to assess the differences in success rate and in incidence of adverse effects by gestational age.

In all, 3,139 women were admitted for incomplete abortion during the study period; 630 required no further treatment. Of the remaining 2,509 women, 21% chose treatment with misoprostol. At all three sites, the proportion of women who chose misoprostol rose between 2008 and 2011 (from 8–12% to 25–28%) but declined in 2012 (to 21–27%). Some 64% of the women treated with misoprostol were 10 or fewer weeks pregnant, 15% were 11–12 weeks, 13% were 13–14 weeks and 8% were 15–18 weeks. Fifty-six percent of women choosing misoprostol received one 800 mcg dose, and 44% required two doses. Sixty-six percent of women with pregnancies of up to 12 weeks required only one dose of misoprostol; this was true for 34% of women who were 13–14 weeks pregnant and 23% of those who were 15–18 weeks pregnant. Only 6% of the women receiving misoprostol were admitted to the hospital; the remaining women were treated as outpatients.

The success rate of treating incomplete abortion with misoprostol differed substantially by gestational age: Ninety-nine percent of pregnancies of 12 or fewer weeks did not require manual vacuum aspiration after misoprostol, compared with 26% of pregnancies of 13–14 weeks and 28% of pregnancies of 15–18 weeks. These successful cases included those in which ultrasound at the 15-day follow-up revealed residue not requiring intervention (4% of women pregnant 12 or fewer weeks, 10% of those pregnant 13–14 weeks and 14% of those pregnant 15–18 weeks). Eight percent of women with pregnancies of 12 or fewer weeks and 3% of those with pregnancies of 13–14 weeks were lost to follow-up and presumed to have had no complications; no woman with a pregnancy of more than 14 weeks failed to return for follow-up.

Following misoprostol administration, 27% of women reported severe pain, 18% experienced chills, 11% felt hyperthermic and 5% had heavy bleeding. The proportion of women reporting adverse effects was lower among those 12 or fewer weeks pregnant than among those with more advanced pregnancies. For example, 8% of women with pregnancies of up to 12 weeks’ gestation experienced severe pain, compared with 93–100% of women with pregnancies of longer durations. Heavy bleeding occurred only among women with pregnancies of more than 12 weeks; 7% of women with pregnancies of 13–14 weeks and 44% of women with pregnancies of 15–18 weeks reported this outcome.

In defending the assumption that the women lost to follow-up were likely not to have required surgical evacuation, the researchers noted that the socioeconomic status of these women indicates that they probably would have sought free care at one of the study’s three sites had additional treatment been required. Also, they note that while the evaluation "shows that [misoprostol] has been very well accepted by both providers and clients," the study’s findings indicate that the drug "did not work…in almost 75% of cases in which gestational age exceeded 12 weeks." Current guidelines recommend using 600 mcg of misoprostol and limiting use to patients with pregnancies up to 12 weeks; the current study confirms those recommendations, the researchers conclude, and indicates that a higher dose is not routinely effective for more advanced pregnancies.—L. Melhado


1. Adisso S et al., Introduction of misoprostol for the treatment of incomplete abortion beyond 12 weeks of pregnancy in Benin, International Journal of Gynecology and Obstetrics, 2014, doi: 10.1016/ j.ijgo.2014.03.002, accessed Sept. 5, 2014.