BRISTOL, England, Dec. 23 (UPI) -- In vitro fertilization is often stopped after three or four cycles and labeled a "failure." A new study in England shows, however, that repeated cycles increase the chances for pregnancy as two-thirds of patients are successful after six or more cycles.
Researchers at the University of Bristol and University of Glasgow found repeated IVF treatments increased the chances for successful pregnancy, contradicting many doctors' current expectations.
One complete IVF cycle is considered the stimulation of ovaries to produce eggs, retrieval of the eggs, and then fresh or frozen transfers of the eggs into the woman. Many doctors, the researchers reported, will dissuade patients from continuing with IVF cycles after three or four.
"Clinicians often dissuade couples from further treatment cycles when they have had one with no eggs retrieved, or imply that results from one such cycle indicate very low chance of future success," said Dr. Debbie Lawlor, a professor at the University of Bristol, in a press release. "Our results suggest that is not the case."
The researchers analyzed medical data on 156,947 women in the United Kingdom who underwent 257,398 IVF cycles between 2003 and 2010. The median start of IVF treatment was at age 35, and median amount of time it took for pregnancy was four years.
Overall, the live birth rate for first cycle was 29.5 percent, and rates remain above 20 percent up to and including the fourth cycle. The cumulative rate for each cycle increased up to the ninth IVF treatment cycle, with 65 percent of women having a live birth by the sixth cycle.
For women younger than 40, live births for the first cycle were at 32 percent, remaining above 20 percent until the fourth cycle, and 68 percent of women achieved a live birth by the sixth cycle. For women between 40 and 42 years old, live births were resulted in 12 percent of first cycles, with six cycles achieving a birth rate of 31.5 percent.
"We need to stop thinking of IVF as a single shot at having a family and think of several cycles as the standard," said Scott Nelson, a professor of reproductive and maternal medicine at the University of Glasgow. "For most couples -- and certainly those where the woman is younger than 40 and those of any age using donor eggs -- two-thirds will achieve a live birth after 5 or 6 treatment cycles. This will take, on average, two years and is similar to rates that couples conceiving naturally take in one year."
The study is published in the Journal of the American Medical Association.