Differential evaluation of human sperm hypoosmotic swelling test and its relationship with the outcome of in-vitro fertilization of human oocytes.

The hypoosmotic swelling test is a simple laboratory test to measure the functional integrity of the human sperm membrane. Its in-vivo and in-vitro applicability needs to be evaluated before it can be accepted as a useful routine test for the fertilizing potential of human semen. We studied the standard semen analysis results and differential sperm tail swelling patterns of seminal and swim-up sperm after hypoosmotic treatment in 97 semen samples used for in-vitro fertilization of human oocytes. Semen samples were classified as infertile (0% fertilization rate; n = 27) or fertile (greater than 0% fertilization rate; n = 70) before statistical analyses. There was a significant difference (P less than 0.005) in percentage normal morphology of seminal sperm between the fertile and infertile semen samples. The percentage normal morphology of seminal sperm correlated (r = 0.4250; P less than 0.005) with the in-vitro fertilization rate of human oocytes and this parameter was selected by the multivariate stepwise discriminant analysis as the discriminator capable of predicting the in-vitro fertilization rate with 57.7% accuracy. The percentage total swelling of seminal and swim-up sperm after hypoosmotic treatment was not correlated with the in-vitro fertilization rate. The percentage swelling pattern g (the open type) of seminal sperm was also selected by the multivariate stepwise discriminant analysis as the discriminator to predict the in-vitro fertilization rate. This parameter correlated with the percentage normal morphology of seminal sperm (r = 0.3014; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)