Objective: To determine time-related cumulative conception rates following conventional in vitro fertilization, taking into account the patients' age and singular causes of infertility. Separate presentation of results for primary and secondary infertility. Patients and methods: Andrological, tubal, endocinological or idiopathic factors were diagnosed as singular causes of infertility in 2713 couples with 5410 cycles, out of a total of 4116 couples with 8112 prospectively documented consecutive cycles. Cumulative conception rates were determined by means of Kaplan-Meier estimates. Differences in rates between primary and secondary infertility and between causes of infertility and age groups were determined with the log-rank test and through Cox-regression. Results: Pregnancies did not occur after the eighth treatment cycle. The cumulative conception rates of couples with secondary infertility were significantly higher than of those with primary infertility (p < 0.01). They were 52% and 43.1%, respectively, after 4 cycles and 79.2% and 54.3%, respectively, after 8 cycles. Compared with other infertility factors, andrological causes of both primary and secondary infertility had the lowest cumulative rates (33% and 39%, respectively, after 4 cycles, and 41% and 77%, respectively, after 8 cycles). The respective rates for tubal causes were 52% (primary infertility) and 56% (secondary infertility) after 4 cycles and 71% and 82%, respectively, after 8 cycles. For endocrinological causes Fates of 39% and 59% could be attained after 3 cycles, and of 86% after 4 cycles in the case of secondary infertility. Idiopathic factors led to rates of 78% after cycles and 91% after 7 cycles in cases of secondary infertility. Conception rates declined significantly (p < 0.001) as a function of the patients' age and were of clinical relevance in the 40-45 year age group. In cases of primary infertility they reached a constant cumulative level of only 12% already after the 2(nd) cycle, and only 33% after the 5(th) cycle in secondary infertility. Conclusion: Cumulative rates of conception following IVF depend on the patients' age, the condition of primary or secondary infertility and the presence of a male factor. In cases of tubal, endocrinological and idiopathic infertility the success of IVF is comparable with the probability of natural conception of young and fertile couples for whom a mean conception rate of 68% after 6 consecutive cycles is cited in the literature.
