Repeated mid-cycle tests of in-vitro sperm penetration (Kremer tests) in healthy women during three menstrual cycles.

The outcome of Kremer testing has been evaluated daily, during the mid-cycle, in 15 healthy women over three menstrual cycles, using a permanent and a variable normal, male donor. There was a significant correlation (r = 0.539; t = 6.33; P less than 0.001, n = 100; Spearman rank correlation with correction for ties) between the results obtained with the two men. The best Kremer test results were seen on the day of the LH peak and the two preceding days. No correlation was present between serum oestradiol levels and Kremer test results except on the day before the LH surge. Enough cervical mucus for Kremer testing was obtained when serum oestradiol levels were a mean of 693 pmol/l (range 214-2140). Variations in Kremer test results obtained in one woman's menstrual cycle were of the same magnitude as the difference between women. Four women had a favourable mid-cycle Kremer test result in all three cycles studied, six women had a favourable mid-cycle Kremer test result during two of their three cycles and five women only during one of the three cycles studied. The outcome of the Kremer test was not directly correlated to the quality of the cervical mucus as evaluated by the scoring system used by WHO. It is suggested that the Kremer test, performed with two male donors daily during the mid-cycle in three menstrual cycles, affords results that will allow reliable prediction of conceptional potential.