RESUMEN
OBJECTIVE: To analyze the different factors influencing real and theoretical cumulative live birth rates following in vitro fertilization. PATIENTS AND METHODS: Retrospective study of 1001 couples starting an IVF/ICSI cycle between 2004 and 2006 that were followed-up after all their attempts. All abandoned cycles were taken in account. RESULTS: For all couples, the theoretical cumulative live birth rates after n attempts were 23.9%, 40.5%, 51.4%, 62.2%. The real cumulative live birth rates were 23.9%, 36%, 41.2% and 44.4%. With reference to age, success rates were better for women less than 35 (58,8%) and were reduced for women older than 38 (18,0%). Looking at the ovarian reserve, in the 35 to 38 years age group, the actuarial rates were satisfactory as long as the ovarian response resulted in five or more oocytes. Among older patients, success rates were influenced by the number of oocytes collected and only acceptable when more than eight oocytes were obtained. Multivariate analysis has demonstrated that women's age was determinant on the live birth rate (OR=0.17 [0.09-0.32] in the 38 to 39 group versus less than 30 group). In ovulatory disease, the success rates were the best compared to other infertility aetiology (OR=1.61[1.05-2.47]). Moreover, the number of embryos transferred had a strong impact on live birth rate with an OR of 1.62 [1.32-1.99] per extra embryo. DISCUSSION AND CONCLUSION: Live birth rates are dependent on the women' age. For women older than 38 years, the ovarian response to the stimulation and the number of embryos transferred are important factors for success.
