[Semen characteristics and quality of the conceptus in fertilization in vitro]

Assisted reproductive technology (ART) is associated with increased risks for the neonate, compared to natural fertility, mainly because of multiple pregnancies and increased maternal age. On the opposite, the impact of paternal factors has been scarcely studied, except for the relationship between surgically retrieved sperms and genetic abnormalities.

This study has been realized using the large French register on in vitro fertilization (FIVNAT) that collects information on 80% of French ART activity. For the study, all the pregnancies obtained from oocyte recoveries between January 1996 and December 2003, for which information on cycles could be linked to the pregnancy were included, i.e. 34223 pregnancies, resulting in 27025 deliveries and 33945 neonates. Sperm quality was defined either according to the semen origin (spouse's ejaculate, epididymis, testis, or donor), or according to the spermiogramme values for concentration, motility and morphology. The statistical analysis included the use of multivariate logistic models, with the main prognostic factors.

The delivery, spontaneous abortion and ectopic pregnancy rates were not influenced by semen origin nor by quality, all the 95% confidence intervals including 1. The neonates conceived through surgically retrieved sperms were at a slightly increased risk of hypotrophy (weight under the 10% centile of reference curves) and of malformation (OR=1.18, 95CI: 1.03-1.36 and OR=1.30 [0,95-1,84], respectively). On the opposite, when analysis was restrained to ejaculated semen, no risk was demonstrated.

The semen quality has little impact on pregnancy issue. Only the semen origin seems to act on hypotrophy and malformation, but these results deserve to be further analyzed for confirmation.