Effect of Sperm Motility on Human In Vitro Fertilization

Abstract

Several sperm motility parameters in semen prepared by the swim-up technique were compared with IVF rates in 84 patients. The patients were either on clomiphene + human menopausal gonadotrophin or follicle stimulating hormone + human menopausal gonadotrophin stimulation regimens. Motility ratings were assessed both manually according to World Health Organization guidelines as well as computer-automated semen analysis (Cellsoft, Cryoresources, USA). Motility ratings of≥ 22 yielded significantly higher fertilization rates (78–82%) than ratings below 2 (20–23%) (p< 0.001) for patients on both regimens. Velocity (41, 55, 78 μm/sec) and mean amplitude of lateral head displacement (1.96, 3.29, 4.91 μm) correlated significantly with and between manual ratings of 1, 2, and 3, respectively (r = 0.83;p < 0.01). No significant differences were observed in linearity and beat/cross frequency between the manual ratings, although beat/cross frequencies tended to reduce linearly with increases in intensity of motility. The velocity of sperm motility has a significant effect on fertilization rates, and cut-off points of ≥2 or ≥50 μm/sec predict the actual potential and likely success of in vitro fertilization. These criteria on the swim-up semen should be used in the selection of patients admitted to IVF programs, and they justify the necessity of research investigations to improve motility in those patients with sluggish motility.

Key Words:

• Spermatozoa
• Fertilization
• IVF
• Motility