Jh. Check et al., RELATIONSHIP OF SUBNORMAL SEMEN PARAMETERS AND SUBSEQUENT ZONA-PELLUCIDA THINNING FOLLOWING IN-VITRO FERTILIZATION, Archives of andrology, 41(3), 1998, pp. 145-150
Infertility due to male factor has been associated with reduced implan
tation rates despite normal fertilization. The mechanism responsible f
or lower pregnancy rates is not known. One cause of failure to achieve
pregnancy despite transfer of embryos is impairment of zona pellucida
(ZP) thinning, which inhibits the embryo from hatching despite initia
l cell cleavage. This study was designed to evaluate whether there is
an association between the ability of the ZP to thin, as measured by Z
P thickness on day of transfer, and subnormal semen parameters. Signif
icant differences in ZP thickness (p < 0.05, Kruskal-Wallis) were note
d according to median concentration of sperm, total motile sperm, and
motile density in that these values were the highest in the group of e
mbryos with the thinnest zona pellucida and lowest in the group with t
he thickest zona pellucida. Thus, some factor may be missing from sper
m from subnormal specimens that normally assists in zona thinning.