Cumulative Live-Birth Rates After In Vitro Fertilization

Abstract

When a couple requires in vitro fertilization (IVF), their main concern is whether this treatment will result in a live birth, not statistics on outcomes per IVF cycle according to maternal age. The cumulative live-birth rate provides a better and more meaningful estimate of a successful pregnancy. Prior studies estimating the cumulative live-birth rate had many deficiencies, including inconsistent inclusion criteria and outcomes, small sample size, and failure to report maternal age or multiple births. This retrospective cohort study estimated cumulative live-birth rates among 6164 patients undergoing their first fresh-embryo, nondonor IVF cycle at a fertility center between 2000 and 2005. Treated patients were followed for at least 1 year until either discontinuation of treatment or a live delivery. Data were analyzed for 2 primary maternal age groups stratified at the start of cycle 1: (a) younger than 35 years, and (b) 40 years or older. Analyses were performed using both optimistic and conservative methods to estimate the cumulative live-birth rate. With the optimistic method, calculation of the cumulative live-birth rate is based on the assumption that patients who did not return for subsequent IVF cycles had the same chance of a live-birth pregnancy as those who remained in treatment. The conservative method calculates the cumulative live-birth rate with the assumption of no live births in patients who did not return for subsequent IVF cycles. Among the 6164 women undergoing up to 6 cycles of IVF, the cumulative live-birth rate was 72% (95% confidence interval [CI], 70%–74%) with the optimistic method, and 51% (95% CI, 49%–52%) with the conservative method. For patients younger than 35 years of age, the optimistic estimate of cumulative live-birth rate after 6 IVF cycles was 86% (95% CI, 83%–88%), and the conservative estimate was 65% (95% CI, 64%–67%). Corresponding rates in patients 40 years of age or older were 42% and 23% (P < 0.001). Among patients 35 years of age or younger and those 40 years or older, both optimistic and conservative cumulative live-birth rates decreased with increasing age. The difference in birth rates between these 2 age-stratified groups was statistically significant (P < 0.001). These data suggest that IVF treatment may overcome infertility in younger women but not in older women. The investigators believe that its apparent inability to completely reverse the age-dependent decrease in fertility should be conveyed to women over 40.