A drug used to induce labor and aid in medical abortions can also serve as a safe, low-cost alternative to surgery for the 1 million American women who experience miscarriages each year, a new federal study shows.

The researchers report in today's New England Journal of Medicine that the hormone-like drug, misoprostol, caused most women to expel remaining uterine contents within a few days.

Misoprostol thus could be an alternative to either a commonly used invasive procedure called vacuum aspiration or simply waiting for the dead fetal tissue to be expelled naturally, which can take up to a month.

But one of the study's co-authors, Dr. Mitchell Creinin of Magee-Womens Hospital, contends that the medical treatment could be even more effective if restrictions were loosened on the use of the abortion pill, mifepristone, or RU-486.

Today's study found that misoprostol was effective in 84 percent of the women with early pregnancy failures, he noted, while the combination of mifepristone and misoprostol has 95 percent efficiency when used to abort live pregnancies.

"We've got to do better for women," Creinin said, contending that U.S. restrictions against use of mifepristone for anything but abortions has the effect of treating women who have miscarried as "second-class citizens."

But it's not clear that mifepristone would necessarily be effective in managing early pregnancy failure, said Dr. Beverly Winikoff, president of Gynuity Health Projects in New York City. And mifepristone would significantly increase the cost of the treatment; the cost of misoprostol is negligible, but each mifepristone pill costs $90, she added.

"I think you'd need a really good piece of evidence before you'd invest in that," said Winikoff. With misoprostol adequate for 84 percent of patients, she reasoned, the additional cost for mifepristone would be wasted in most cases.

"In theory, [mifepristone and misoprostol] probably would be more effective," said Dr. Jun Zhang of the National Institute of Child Health and Human Development, lead author of the miscarriage study, "but I'd have to see some concrete numbers to back up this statement." The abortion pill also carries considerable stigma, he added.

Creinin said he is within a patient or two of finishing a 30-patient pilot study at Magee of the mifepristone-misoprostol treatment for miscarriage. If it shows a benefit, he hopes to secure funding for a larger study.

Though doctors not involved in a research study can't use mifepristone for anything but abortion, no such restrictions apply for misoprostol, a drug originally approved for reducing the risk of stomach ulcers in people taking arthritis pain relievers.

Perhaps because of their experience in using the drug in medical abortions, some physicians already have begun prescribing misoprostol to women suffering miscarriages. Zhang said he expects that practice will pick up in light of the new study, which found few side effects and noted that four out of five women were pleased with it.

"I hope women are given a choice," Winikoff said. "It's really a big convenience for women." The drug can be prescribed as soon as the miscarriage is diagnosed, she noted, so no return trip is necessary as is often the case when a surgical procedure is used.