Purpose: Based on data from the literature, to detect the possible presence of an increased frequency of meiotic anomalies in oligoasthenozoospermic (OA) patients preselected for intracytoplasmic sperm injection.
Methods: Meiotic studies in as many successive patients with a clinical indication for a diagnostic testicular biopsy as needed to complete at least 100 cases with a severe OA (motile sperm concentration < or = 1.5 x 10(6)/ml).
Results: An increased incidence of meiotic anomalies was found in 102 patients with a severe OA (17.6%) compared to the mean for 105 patients with other etiologies in the series (5.7%) or the mean for patients reviewed in the literature (6.5%).
Conclusions: Patients with a severe OA have a higher incidence of synaptic anomalies. This may result in the malsegregation of chromosomes at meiosis I, producing abnormal sperm, and could explain the high incidence of sterility and some cases of abortion (in two thirds of the couples with abortions the husband had meiotic anomalies) in this group.