Cut-off value of reactive oxygen species for predicting semen quality and fertilization outcome

Though the role of reactive oxygen species (ROS) in male infertility is widely investigated worldwide, there is a lack of adequate information on the cut-off value of ROS beyond which ART outcome may be adversely affected. The objective of the present study is to establish an upper level of ROS in semen samples which can be considered as a potential marker of good semen quality. Semen ejaculates were randomly collected from 338 male partners of infertile couples. The upper critical limit (UCL) of ROS was calculated from the control chart of normozoospermic patients and found to be 0.75 x 10(6) counted photons per minute (cpm)/10 million cells. This was further validated by estimating ROS in 17 proven fertile men and 38 patients undergoing intra cytoplasmic sperm injection (ICSI). As expected, all abnormal semen samples exhibited higher ROS as compared to nomozoospermic and proven fertile samples. All semen samples from proven fertile volunteers were found to be < 0.075 x 10(6) cpm/10 million cells. On the basis of the calculated UCL, ICSI patients were divided into two groups: Group I (< UCL) and Group II (> UCL). The semen parameters, fertilization rate and pregnancy outcome were found to be significantly affected in Group II. Significant difference in live birth-rates was observed between Group I (47.6%) and Group II (17.6%) while no live-birth was recorded for ROS level > 0.1 x 10(6) cpm/10 million cells. It is concluded that the upper cut-off value of normal semen samples that correlates with good semen quality is, therefore, in the order of 0.075-0.1 x 10(6) cpm/10 million cells. in addition to the WHO [1999] semen analysis, this range is expected to assist andrologists and clinicians in predicting semen quality and fertilization outcome in patients with male factor infertility undergoing ICSI.