Assessment of fertility by sperm mechanical energy using computer-assisted sperm analysis system

Abstract

Purpose: It is known that the energy distribution of sperm obeys the following equations and the total mechanical energy in a sperm population is expressed as nKλ × a constant. nKλ/102 is defined as the sperm energy index (SEI). P = C/√t (eλ)Kt/t 1/C = ∫0infin 1/√t (eλ)Kt/t dt Here, P is the existing probability density of sperm, t is the square of amplitude of lateral head displacement, λ is the mean of t, n is the number of motile sperm in semen in a measurement field, and K is a constant determined for each semen sample. These values can be obtained with the use of computer-assisted sperm analysis (CASA). Methods: Sperm motility parameters were measured using CASA in 163 ejaculated semen samples from 47 infertile men (infertility group), and 162 ejaculated semen samples from 45 fertile men (natural pregnancy group). Kλ is defined for the present investigation as the mean energy index (MEI). SEI and MEI were obtained according to the methods described in sperm energy theory. Results: There were no natural pregnancy subjects with SEI < 0.5. All subjects with MEI > 2.0 and SEI > 1.0 were in the natural pregnancy group. Conclusions: An assessment of fertility was possible by using the sperm energy index. © Japan Society for Reproductive Medicine 2008.