A recent inquiry into maternal deaths in the United Kingdom found that OHSS following high-dose IVF is now one of the leading causes of maternal mortality in England and Wales. But it may not be the only complication. One recent study suggested that high-dose IVF contributes to lower birth weights, compared with the babies of women who receive minimal doses of hormones. And experts have debated for decades whether IVF contributes to an increased risk of breast and ovarian cancer; studies have reached conflicting conclusions.

Lupron, used to suppress the ovaries, has raised concerns as well. The drug is approved to treat prostate cancer; its use in IVF is off-label (meaning it is not FDA-approved for this purpose). Thousands of women have reported adverse reactions, including memory loss, liver disorders, bone loss and severe muscle, joint and bone pain, said Marcy Darnovsky, associate executive director of the Center for Genetics and Society, a public interest group in Berkeley, Calif.

“Lots of drugs are used off-label, but is this use appropriate?” said Ms. Darnovsky. “Considering the number of women who’ve taken these drugs over the past 25 years, you’d think much more rigorous studies and analysis would have been done on them.”

Because of these concerns, some reproductive specialists are switching to a milder form of IVF. The low-dose technique relies on fewer drugs to stimulate the ovaries, and can result in fewer complications and a quicker recovery time.

Dr. Pasquale Patrizio, a professor of obstetrics and gynecology at Yale University and director of the Yale Fertility Center, said he has been using low-dose IVF with good results. “It’s a shift of minds in the last few years, as we’ve been realizing that there’s no need to stimulate ovaries so aggressively as we’ve done before,” he said.

But other experts say that because the low-dose method produces fewer eggs, women have lower pregnancy rates per cycle. It could take more cycles, and perhaps more money, for a woman to conceive.

“By doing more cycles, there are greater risks by exposing women to more medication, more egg retrievals, and more anesthesia,” said Dr. Schattman of NewYork-Presbyterian/Weill Cornell Medical Center. “It’s not patient-friendly, and you’ll find lots of doctors who don’t agree with it.”