Biomedical subjects
Publications and source records attributed to FIVNAT.
From 1986 to 2002, 16,618 twin babies have been reported to FIVNAT. Mean length of gestation was 36.74 weeks. The mean weight was 2413 g and mean height 46 cm. The proportion of prematurity under 28 weeks of amenorrhea was 1.17% and under 33 weeks: 7.78%. These data are similar to those reported in the French AUDIPOG Report.
In 2002, FIVNAT has continued its study on the use and the results of the ovarian stimulation protocols using GnRH antagonist for i.v.f. and i.c.s.i. The first part of this study demonstrates that the antagonist protocols were still used in more pejorative cases than the long agonist protocols but with a smaller difference compared to 2001. So far, the frequency of the antagonist protocols has jumped from 13% to 19% from 2001 to 2002. This increase was mainly at the expense of the long agonist protocols. In the overall population, the lower pregnancy rate per ovum pick-up with antagonists, demonstrated in 2001, has been confirmed. In the second part of the study, FIVNAT has selected a good prognosis group (women's age less than 35 years and attempts rank lower than 3). This group includes 17,532 cycles with agonists and 3229 cycles with antagonists. A comparison of all the biological and clinical data was made. Finally, the pregnancy rate per ovum pick-up was significantly reduced when the stimulation was done with an antagonist protocol (Anta) rather than with a long agonist protocol (Ago). In i.v.f. these rates were 20.8% (Anta) versus 25.8% (Ago) (P < 0.001). In i.c.s.i. they were 21.9% (Anta) versus 29.4% (Ago) (P < 0.001). Moreover, the absolute and relative differences were the same in 2001 and 2002, suggesting that the learning curve effect does not explain the differences.
The proportion of women over 40 in i.v.f. and in i.c.s.i. has been dramatically increasing to reach 12% in 2002. Tubal and unexplained infertility increases with age. Short protocols or protocols with GnRH antagonists are more and more often used for older women. Best results are nevertheless still obtained with long protocols! Up to 35 years, pregnancy rates are similar with two or three transferred embryos. Over 35, better results are observed with three embryos. However, the rate of twins only falls below 20% when the woman is over 38, in i.v.f. as well as in i.c.s.i. The decreasing pregnancy rate should be better known by patients and clinicians so that women are treated sooner for i.v.f.