Objective. To examine the relationship of 24-h sperm motility between post insemination and fertilization in vitro, in a population with no apparent semen abnormalities. A retrospective study from July 1998 to June 2000.
Material and methods. Four hundred and seventy-one consecutive in-vitro fertilization (IVF) cycles for which the primary diagnosis was not male infertility (total motility count > 40 × 106) were studied. Linear regression was used to examine the general relation between 24-h sperm motility and IVF. The cohort with 0% 24-h motility was compared with all other cycles using the t-test and the χ2-test. Test quality was assessed using the positive likelihood ratio.
Results. Overall fertilization was 58 ± 16%. There were 45/471 cycles (9.5%) with zero fertilization. Linear regression of percent fertilization vs. 24-h motility showed no relationship (r = 0.01). The cohort with 0% 24-h motility had a lower fertilization rate 29 ± 19% (P = 0.05), and had a higher incidence of no fertilization 7/21 (P = 0.01). The positive likelihood ratio was 4.6.
Conclusions. Zero 24-h motility indicates occult male infertility, and a positive result indicates a fair to good test. Overall there was no relationship between sperm survival at 24 h post insemination and fertilization in vitro. However, 0% 24-h sperm motility was associated with reduced fertilization