New research published in the Journal of the American Medical Association found that “nearly two-thirds of women undergoing I.V.F. will have a child by the sixth attempt, suggesting that persistence can pay off, especially for women under 40.” The study looked at nearly 157,000 women in the UK who together underwent over 257,000 IVF cycles between 2003 and 2010. Researchers found that the “live birthrate 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.”
The numbers should actually be higher today because IVF success rates have increased significantly since the time this study was done, 2003-2010.
Smith and colleagues examined data from 156,947 U.K. women receiving 257,398 IVF ovarian stimulation cycles from 2003 to 2010, with follow-up until June 2012. The median duration of infertility was 4 years, and 85% of the women were under age 40.
Women ages 40-42 achieved only a 12.3% live birth rate after the first cycle. Rates remained above 20% through four cycles when examining all women, with a 29.5% live birth rate after the first cycle.
The rate after the first cycle was almost a third for younger women under age 40 who used their own eggs (32.3%).
But the rate of success dramatically declined for women over age 42, with all rates in each cycle less than 4%. However, this was only when women used their own eggs. When women used donor eggs, the age differential was removed, with live birth rates at 29.6% or greater for all cycles up to and including the ninth.
One study limitation was how patients who discontinue IVF are treated. Another was the lack of data about pretreatment reproductive hormone levels, smoking, and body mass index, which have all been linked to live birth rates. Finally, the authors were only able to assess live birth as an outcome.
“Future studies should also consider potential adverse events of continued treatment, including ovarian hyperstimulation syndrome and possible increased risk of preterm birth, low birth weight, or congenital anomalies,” they concluded.
Three or four unsuccessful cycles is usually labeled “repeat implantation failure,” and the authors said that their findings support the efficacy of extending the number of IVF cycles. But an accompanying editorial by Evan R. Myers, MD, MPH, of Duke University in Durham, N.C., pointed out that despite the increase in success with multiple cycles, U.S. insurance may present a problem.
“For insurers who cover a specific number of [assisted reproductive therapy] cycles, the incremental cost-effectiveness of each additional cycle is unclear, at least in part because of the methodological complexities involved in economic assessments of fertility treatments,” he wrote.
Another issue is the difference between the U.K. and U.S. population in terms of the duration of infertility prior to IVF being an option.
“For example, recommendations by the National Institute for Health and Care Excellence (a U.K. public body that develops clinical guidelines based on evaluations of efficacy and cost-effectiveness) on the duration of infertility prior to offering IVF (3 years for women aged <35 years during the period covered by the study) and number of covered IVF cycles (up to three) suggest that the duration of infertility among the U.K. couples was likely longer than among couples in the United States (which would suggest potentially higher success rates in the United States),” he explained. This limits the generalizability of the results, Myers added.
But he noted that “for clinicians, it is important that these data be shared with couples so that they can make a truly informed decisions. This will require time and expertise in communication.”