ART success and in vivo sperm cell selection depend on the ultramorphological status of spermatozoa

Management of male infertility has recently shifted from treatment of the s ubfertile man towards techniques of assisted reproduction (ART). This study aimed to evaluate the possible role of the ultramorphological status of th e spermatozoon with respect to sperm selection in vivo and prediction of AR T success. Ultramorphological sperm parameters were assessed retrospectivel y for 92 males with sufficient sperm density (10(7) spermatozoa ejaculate(- 1)) whose wives conceived following a stepwise discarding of the female gen ital tract barriers, using intra-uterine insemination (IUI) (n = 26), in vi tro fertilization (IVF) (n = 45) or intracytoplasmic sperm injection (ICSI) (n = 21). In parallel, sperm samples of 71 fertile males were examined. No rmal ultramorphology of all head and tail subcellular organelles was found to be essential for the ability of spermatozoa to pass the lower female gen ital tract. The ultramorphological migration threshold for this barrier is apparently higher than that essential for oocyte fertilization. No specific indication associated with passage through the upper genital tract was fou nd. A high prevalence of axonema defects was found to impair the ability of sperm cells to penetrate the oocyte investment. The natural fertility inde x, based on routine sperm parameters and the ultrastructural status of the spermatozoon's subcellular organelles was confirmed to be beneficial for di recting patients to ART. A discriminative score based on axonema integrity was found to contribute additional information for the first choice decisio n between conventional ART and ICSI (75% prediction ability). Thus it may b e helpful in finding the simplest and least expensive procedure with the gr eatest long-term chance for pregnancy.