With in vitro fertilization, persistence pays off, study suggests

In their quest to become parents, most infertile couples undergoing in vitro fertilization must grapple with a tough decision: when to call it quits. After three or four unsuccessful embryo transfers, doctors have long assumed that the chances of eventually bringing home a child were dismal.

But a large study, published Tuesday in the Journal of the American Medical Association, has found that nearly two-thirds of women undergoing IVF will have a child by the sixth attempt, suggesting that persistence can pay off, especially for women under 40.

The cumulative rate for live births continues to increase, albeit modestly, up to the ninth attempt, or "cycle" of IVF.

"The take-home message is your prognosis doesn't fall off a cliff if it didn't work after three or four cycles," said Dr. Owen Davis, president of the American Society for Reproductive Medicine, who was not involved in the new research.

But while some infertile couples may find the result reassuring, experts noted, many others are likely to struggle with the expense and emotional upheaval of repeated treatments.

The study included nearly 157,000 women in the United Kingdom who together underwent more than 257,000 cycles of IVF treatment between 2003 and 2010.

Researchers at the University of Bristol and the University of Glasgow defined a cycle as stimulation of ovaries to produce several eggs, plus all the resulting embryo transfers. These days, doctors are now encouraged to transfer just one or two embryos at a time to avoid multiple births. The rest are frozen for later attempts.

The live birth rate for participants after the first cycle in the new study was 29.5 percent, compared with 20.5 percent after the fourth cycle, 17.4 percent after the sixth cycle, and 15.7 percent after the ninth cycle.

"It's never been shown in a large population before that that could be the case," said Dr. Evan Myers, a professor of obstetrics and gynecology at the Duke University Medical Center. "Instead of saying, 'If you haven't been successful after three or four cycles, think about donor eggs or adoption,' the study says, 'If you keep going, there's still a substantial chance.' "

Age made a big difference in the study. The live birth rate among women younger than 40 after the first cycle was 32.3 percent, and after the sixth cycle, 17 percent. But among women ages 40 to 42, just 12.3 percent were successful after the first cycle, and only 6.9 percent after the sixth.