Abnormal sperm-mucus penetration test predicts low in vitro fertilization ability of apparently normal semen

To investigate whether Kremer’s sperm-mucus penetration test may predict sperm fertilizing ability in IVF. Kremer’s test was prospectively performed on semen samples used for 66 consecutive IVF trials and compared with the fertilization rates and fertilization failure rates observed. Fertilization rates were significantly reduced in cases of abnormal Kremer’s test (42% versus 51%; n=745 oocytes with a statistically insignificant increase in fertilization failure rates (21% versus 10%; n=66 trials). For abnormal semen, fertilization rates (39% versus 39%; n=208 oocytes) and fertilization failure rates (20% versus 28%; n=17 trials) were similar regardless of Kremer’s test result. For normal semen, an abnormal Kremer’s test implied a significant decrease in fertilization rates (44% versus 54%; n=537 oocytes) with a statistically insignificant increase in fertilization failure rates (21% versus 6%; n=49 trials). Abnormal Kremer’s test results identify patients with a decreased in vitro fertilizing ability despite apparently normal semen samples and a group with very low fertilizing failure risk in case of normal semen samples and normal Kremer’s test. Kremer’s test does not add any predictive value to sperm analysis in the case of abnormal semen samples. These observations point out the importance of the male factor in fertilization failure even in the case of normal semen analysis.