MILK VERSUS TEST-YOLK - PREINCUBATED SPERM - IN-VITRO FERTILIZATION OUTCOME

Objective: Preincubation of sperm in TEST-yolk medium enhances in vitr o fertilization (IVF) outcome. However preincubation of sperm in milk at 5 degrees C enhances the results of sperm penetration assay and hem izona assay. This study was therefore performed to determine the influ ence of milk on in vitro fertilization rate of human oocytes, as compa red with TEST-yolk medium. Study design: Forty-one consecutive couples undergoing an IVF procedure were randomized. Of these 20 couples were admitted for the milk study (group 1) and 21 couples for the TEST-yol k study (group 2). Each ejaculate was Percoll-processed and the sperm pellet was resuspended in 0.5 ml of culture medium. An equal volume of heat-inactivated homogenized cow's milk (95 degrees C, 10 min) was ad ded to sperm suspension from group 1 and an equal volume of TEST-yolk medium was added to sperm suspension from group 2. After 2 h of incuba tion at 5 degrees C and washing with culture medium at 37 degrees C, o ocytes were inseminated. Oocytes from group 1 couples were inseminated with milk-treated spermatozoa and those from group 2 couples with yol k-treated spermatozoa. Oocytes were evaluated for fertilization after 18 h. Results: Sperm preincubated in milk fertilized 75 out of 100 mat ure oocytes (75%). TEST-yolk-treated sperm fertilized 45 out of 64 mat ure oocytes (70%). The difference was not statistically significant. C onclusions: Preincubation of spermatozoa in milk, as compared with pre incubation in TEST-yolk medium yields a similar IVF outcome, so milk m ay be a suitable alternative medium for preincubation of spermatozoa t o enhance its fertilizing potential.