CUMULATIVE CONCEPTION AND LIVEBIRTH RATES AFTER INVITRO FERTILIZATION

Cumulative conception and livebirth rates related to age and cause of infertility provide the most useful estimate of success after in-vitro fertilisation (IVF), but limited data are available. It is also uncertain whether the probability of pregnancy, livebirth, and pregnancy failure changes with repeated treatment cycles. To assess the effects of patients' age and cause of infertility on these outcomes, we studied the results of 5055 consecutive IVF cycles (773 clinical pregnancies, 518 livebirths) undertaken on 2735 patients in a single IVF unit. Cumulative conception and livebirth rates were analysed by the life-table approach and differences in rates between age-groups and between causes of infertility were measured by the log-rank test and logistic regression modelling. Both conception and livebirth rates per cycle declined with age (p < 0.001), and cumulative conception and livebirth rates after five treatment cycles were about 54% and 45%, respectively, at 20-34 years, compared with 38.7% and 28.9% at 35-39 years and 20.2% and 14.4% at greater-than-or-equal-to 40 years. The two rates were significantly different between causal groups (p < 0.001 and p = 0.02, respectively) and were lowest in patients with male infertility or multiple infertility factors. The pregnancy failure rate was higher (p = 0.006) in women over the age of 34 years and there was a significant decline in the chances of pregnancy and livebirth per cycle with successive treatment cycles. The success of IVF compares favourably with that of spontaneous conception in the natural menstrual cycle. For women up to the age of 34 years, almost 55% will become pregnant and 45% will have a livebirth within five cycles of treatment.