The G.D. Searle and Pfizer Inc. drug Cytotec is almost as effective as surgery for removing tissue that can remain in the uterus after a failed pregnancy, a test released on Wednesday has shown.

The drug, also known by its generic name misoprostol, had a success rate of around 85 percent, said Jun Zhang of the National Institute of Child Health and Human Development, the chief author of the study.

The treatment, which can be done on an outpatient basis, is less risky than surgery and the pills costing up to 50 cents can be inserted into the vagina at home, he told Reuters.

The results “show that this treatment may be an option that is preferable to surgery for some women,” said Beverly Winikoff in an editorial in the New England Journal of Medicine, where the study appears.

About one in four women will have a spontaneous abortion or some other type of failed pregnancy. If some tissue is left in the uterus, doctors may advise waiting up to a month so it can be expelled naturally, but that does not always work.

For women who don’t want to wait, the traditional alternative has been a D&C, which stands for dilation and curettage and involves a surgical scraping of the uterus. A newer technique uses a vacuum to clean the uterus.

To see if Cytotec, which causes uterine contractions and is given after the abortion pill RU-486, is a safe and acceptable alternative, the Zhang team gave it to 491 women who had residual tissue after their pregnancies failed.

They found that it worked in 71 percent of the women by the third day. The remaining women got a second 800 microgram dose, and the success rate increased to 84 percent by the eighth day. The surgery was successful in 97 percent of the 161 who received the vacuum technique.

Eighty-three percent of the Cytotec recipients said they would recommended it to women in the same situation.

“The drug is quite effective,” Zhang said. “It usually takes effect in four hours, when you have uterine contractions and the crampy abdominal pain comes. After that, usually the abdominal pain will disappear quickly.”

There can be side effects such as some nausea, diarrhea and vomiting.

Winikoff, president of the Gynuity Health Projects in New York, said questions persist about the best dose to use and whether the cause of the failed pregnancy should influence the dose.