The split ejaculate: assessment of fertility potential using two in vitro test systems.

Semen samples (split & whole ejaculates) were obtained from 12 normal men (group A) and 8 oligospermic infertile men with sperm concentrations of less than 20 x 10(6) sperm/ml (group B). All samples were evaluated by standard semen analysis, bovine cervical mucus penetration assay (CMPT), and, in all cases with sufficient sperm, in the human spermatozoa zona-free hamster in vitro penetration assay (SPA). In group A the motile sperm concentration was significantly higher in the ejaculated material of the first two contractions (fraction I or FI) than in the remainder of the ejaculate (fraction II or FII) (p less than 0.02). No significant differences were observed in sperm penetration into zona-free hamster ova or bovine cervical mucus by sperm from FI, FII or the whole ejaculate. Motile sperm concentration was significantly correlated with sperm penetration into bovine cervical mucus (r = 0.65, p less than 0.01), but not into zona-free hamster ova (r = 0.01 NS). In the samples collected by group B, the mean sperm concentration and motile sperm concentration were higher in the first (FI) than in the second (FII) fractions of the split ejaculate or the whole ejaculate (p less than 0.05). No significant differences were found among the FI, FII and the whole ejaculate semen samples for penetration of sperm into bovine cervical mucus. Sperm concentration and motile sperm concentration were significantly correlated with sperm penetration into bovine cervical mucus (r = 0.58, p less than 0.01 and r = 0.57, p less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)