[FIVNAT. Influence of attempt rank in in vitro fertilization].

The French national register on in vitro fertilization (IVF) FIVNAT, which has collected most of the oocyte pick-ups realised in France since 1986 has allowed us to build a cohort of 35,714 couples, of which the first recovery took place between 1990 and 1994 and followed up to a pregnancy or to the 31st of december, 1996. The per recovery clinical pregnancy rate decreased from 20.2% on the first attempt to 17.4% on the second, and to less than 13% after the sixth. This evolution existed whatever the women's age class or the infertility diagnosis. The women's age remained the most important factor, since the cumulative pregnancy rate decreased from 60% for women aged less than 35 years to 17% for those aged more than 41 years. Among the indications, male infertility using spouse's semen had the poorest prognosis, especially for women aged more than 41 years (9.6%) whereas male infertility using donor's semen among women aged less than 35 years was associated to the best results (68%). It must be noticed than a high percentage of unpregnant women did not come again for a further recovery (40% to 50%). Then, the crude cumulative birth rate (24.4%) was far below the theoretical cumulative one(54.2%).