Male factors and the likelihood of pregnancy in infertile couples. II. Study of clinical characteristics--practical consequences.

A prospective study of 394 infertile men was conducted over 3 years following a primary semen analysis. Simple comparisons between the groups of men whose partners conceived and those that did not, showed that the mean duration of infertility in the primary infertile group was significantly shorter when a pregnancy was observed, while age differed significantly between the two populations in the secondary infertile group. Multivariate analyses, taking these variables and sperm characteristics into account, showed that prognostic variables for the occurrence of pregnancy were the duration of infertility, sperm motility and the multiple anomalies index in the primary infertile group, and age of the male partner and percentage of normal sperm in the secondary infertile group. Tables for estimating the probability of observing a pregnancy as a function of these criteria are presented. In this study no positive influence of treatment on the occurrence of a pregnancy was found during the 3 years following the first semen analysis.