Semen parameters, including WHO and strict criteria morphology, in a fertile and subfertile population: an effort towards standardization of in-vivo thresholds

Abstract

In this study, the semen analysis results of a fertile population were compared with those from a subfertile population, in order to establish normal cut-off values for the standard semen parameters with the aid of receiver operating characteristic (ROC) curve analysis. The fertile group comprised healthy males (n = 107) without any history of fertility problems, the partners of whom had had a spontaneous pregnancy within one year of unprotected intercourse and were pregnant at the time of the male's inclusion into the study. A total of 103 males from couples attending the infertility clinic, and with an initial sperm count of <20x10(6)/ml were recruited to form the subfertile population. The best discriminating parameter between the two populations was sperm morphology evaluated according to WHO criteria at a cut-off point of 31% normal spermatozoa. The other cut-off values were at 8% for the acrosome index, 45% for motility, and 4% normal spermatozoa for strict criteria. Recalculating the ROC curve cut-off values based on an assumed 50% prevalence of subfertility in an assisted reproductive setting, the cut-off points were reduced to 21% and 3% normal spermatozoa for WHO and strict criteria respectively. For motility, the new cut-off value was at 20% motile spermatozoa, for motility quality at 3.5 (on a scale of 1-6), the acrosome index at 3% normal acrosomes, and the teratozoospermia index at 2.09.

What is New in the Clinical Assessment and Treatment of the Infertile Male

“…One-sided lower reference limits (the fifth centile) were generated and have been proposed to be considered the lower cut-off limits for normality. Apart from total sperm number per ejaculate, the lower limits of these distributions are lower than that of previously presented 'normal' or 'reference' values [3][4][5] but are in agreement with recent observations [6][7][8].…”

Gonad evaluation in male systemic lupus erythematosus

“…The interpretation of these results, regarding the chance of conception for all male lupus patients classified as subfertile in the present study, is hampered by the recent debate concerning the cutoff values for normality in these 2 conventional techniques of semen evaluation. In fact, they do not seem to be the ideal assessment of male fertility potential, and reductions in the cutoff points have been proposed for WHO guidelines and Kruger strict criteria morphology (30)(31)(32).…”

Semen analysis with regard to sperm number, sperm morphology and functional aspects

“…Liu et al [26] also fall into the same group, and they wrote that 'Normal sperm morphology (zona pellucida-bound, %)' was the same in the fertile and infertile groups (60% vs. 54%; not significantly different). Menkveld et al [24] came to the following conclusion: 'For sperm morphology evaluated according to WHO criteria (1992-traditional method), the best cut-off point to identify the males with a possible subfertility problem based on the results of the fertile and subfertile populations investigated in this study was ≤ 30% morphologically normal spermatozoa with a sensitivity and specificity of 74.5% and 76.6%, respectively. For strict criteria, the cut-off point was ≤ 4% morphologically normal spermatozoa with a sensitivity of 74.5% and a specificity of 77.4%'.…”

“…These facts ought to be viewed in the light of the claims that the 'Tygerberg strict criteria' are supported by a 'myriad of publications' (e.g., [20]). Section 2.13.2 of the new WHO manual [6] states, 'By the strict application of certain criteria of sperm morphology, relationships between the percentage of normal forms and various fertility endpoints (TTP, pregnancy rates in vivo and in vitro) have been established (Eggert-Kruse et al [21]; Jouannet et al [22]; Coetzee et al [18]; Toner et al [23]; Menkveld et al [24]; Van Waart et al [19]; Garrett et al [25]; Liu et al [26]) that may be useful for the prognosis of fertility'. Hopefully these authors used 'strict application of (their own) criteria', but that is not to be confused with the application of 'strict criteria'.…”