D. Feneux

A prospective study of 394 infertile men was conducted over 3 years following a primary semen analysis. The cumulative pregnancy rate was 43 and 64% after 1 and 3 years, respectively. The pregnancy rate was significantly higher in the secondary infertile group. The study of various sperm factors and the occurrence of pregnancy showed that they were not of equal significance in predicting male fertility potential. The percentage of pregnancies decreased significantly only when the sperm concentration was less than 5 x 10(6)/ml. The pregnancy rate increased significantly with the percentage of motile sperm. The percentage of sperm with normal morphology was also found to be significantly higher when a pregnancy occurred than when the couple remained infertile (43.6% vs 37.7%). In a detailed morphological analysis of the sperm, six abnormalities (microcephaly, double head, amorphous head, cytoplasmic droplet, bent tail and coiled tail) were found to be significantly more frequent when a pregnancy did not occur. The most predictive value was given by the Multiple Anomalies Index (MAI), which is the mean number of abnormalities observed per abnormal sperm. The pregnancy rate was significantly lower after both 1 and 3 years when the MAI was greater than 1.6. Multivariate analysis showed that the best prognostic indicator of fertility was given by the percentage of motile sperm and the MAI, particularly in patients with primary infertility.

Two groups of men were retrospectively selected according to their observed success in in-vitro fertilization. Seminal and post-migration sperm samples from a low fertilization rate group (less than or equal to 33% cleaved embryos) have been compared to results obtained from a high fertilization rate group (greater than or equal to 66%). It was found that a low mean value of the amplitude of lateral sperm head displacement and an increased percentage of abnormal acrosomes were related to in-vitro fertilization failure. None of the individual sperm factors studied was found to determine in-vitro fertilization success with certainty; only when they were considered in combination was it possible to predict the likelihood of successful in-vitro fertilization of human oocytes.

The absence of outer dynein arms in the sperm flagellum induces an abnormal movement pattern associated with male infertility. These spermatozoa can decondense in zona-free hamster oocytes but result in a very low fertilization rate in in vitro fertilization. We hypothesized that subzonal insemination could help achieve fertilization and pregnancy. A randomized prospective trial (five couples, five cycles) comparing subzonal insemination (n = 31 oocytes) and routine IVF (n = 23 oocytes) was carried out. Oocytes were microinjected with 8.5 +/- 3.6 spermatozoa. In a second series (nine cycles), all the oocytes were microinjected with 10.5 +/- 4.3 spermatozoa. In the randomized series, the fertilization rate was 16.1% without polyploidy, whereas no fertilization was obtained after control IVF insemination. In the second series involving nine couples, six of whom were included in the first series, the fertilization rate increased to 57.8% with a 27.8% polyspermic rate. Eighty-eight per cent of the zygotes cleaved normally (29 out of 33). A total of 11 embryo transfers resulted in three pregnancies, one of which terminated one month later, a second being ongoing and the third delivering a healthy girl. A 21.4% pregnancy rate per cycle, with a 37.5% pregnancy rate per couple, justifies the use of subzonal insemination to treat this particular flagellar dyskinesia.