Updated

Laughter may not be the best medicine, but it might help women who are trying to become pregnant through in-vitro fertilization (IVF), a small study suggests.

In a study of 219 women undergoing IVF, Israeli researchers found the odds of success were greater among women who were entertained by a professional "medical clown" right after they had the embryos implanted in the womb.

Overall, 36 percent became pregnant, versus 20 percent of women who'd had a comedy-free recovery after embryo implantation.

The findings appear in the journal Fertility and Sterility, and expand on research the Israeli group had presented earlier at a conference.

Dr. Shevach Friedler, who led the work, said he got the idea for the study after reading about the potential physiological effects of laughter as a "natural anti-stress mechanism."

"Patients suffering from infertility undergoing IVF are exceptionally stressed," said Friedler, who is based at Assaf Harofeh Medical Center in Zrifin.

"So I thought that this intervention could be beneficial for them at the crucial moments after embryo transfer," Friedler told Reuters Health in an email.

To test the idea, Friedler's team had a medical clown visit their fertility clinic periodically over one year. Of the 219 women in the study, half underwent embryo implantation on a day the clown was at the clinic.

During recovery from the procedure, each woman had a 15-minute visit from the clown, who performed a specific routine created by Friedler, who has studied movement and mime -- and a colleague.

The researchers found that compared with women who came to the clinic on a "non-clown" day, those who'd had a laugh were more than twice as likely to become pregnant, when other factors, like age, type of infertility and the number of embryos implanted, were taken into account.

Whether other fertility clinics are going to start sending in the clowns is anyone's guess. But Friedler added that if studies at other centers back up his findings, fertility clinics elsewhere might take up the tactic.

"After all," he noted, "this is one of the least hazardous interventions in our field."

Asked whether other stress-reducing techniques might be useful, Friedler said further studies are needed to answer that question.

It's not clear, he noted, that the clown intervention actually worked by curbing stress. And in general, researchers are not sure what role emotional stress might play in IVF success.

So-called "clown care" has long been used at medical centers in Israel, the U.S., Canada, Europe and Australia, usually in children's hospitals.

It's also gaining some academic backing. The University of Haifa in Israel, for example, recently launched a degree program in "medical clowning."