The overall live-birth rate after six cycles of IVF was between 51 percent and 72 percent. For women under 35, the rate was 65 percent to 86 percent. The rates differed, because not all women returned for all six cycles, the researchers said.
So, the researchers developed a best-case and worst-case scenario to account for these women. The highest number assumes that the women who stopped IVF treatments would have had a baby, and the lower number assumes that none of them would have. The actual number likely lies somewhere in between those two scenarios.
Penzias said that means that women under 35 who go through IVF have roughly the same chance of having a baby as someone who's a similar age in the general population.
The live-birth rate decreased as the age of the women increased, and women over 40 had only between a 23 percent to 42 percent chance of having a baby.
Overall, about 70 percent of the women had one baby, and less than 30 percent had twins. Fewer than 2 percent had triplets, according to the study.
"It's not a surprise to know that if you do more than one IVF cycle, you have a better chance of having a baby, but this study gives an indication of what one can expect if one is going to do IVF and try it multiple times," said Grifo, who added that the bottom line is, "that for any one woman, each cycle is either 100 percent or zero percent."
To learn more about in vitro fertilization, visit the American Pregnancy Association.
SOURCES: Alan S. Penzias,
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