DEFINITION OF THE POTENTIALLY FERTILE PERIOD FROM URINARY STEROID-EXCRETION RATES - PART-II - A THRESHOLD VALUE FOR PREGNANEDIOL GLUCURONIDE AS A MARKER FOR THE END OF THE POTENTIALLY FERTILE PERIOD IN THE HUMAN MENSTRUAL-CYCLE

Application of time series analysis to a database containing serial pr egnanediol data from 113 complete ovulatory menstrual cycles contribut ed by 83 women of proven fertility and 68 cycles for which pregnanedio l values were available over the ovulatory period detected the first s tatistically significant rise in pregnanediol excretion for all cycles for which a baseline was available (n = 170). However, even at the 99 % confidence level, for 22% of cycles a rise was observed before the p resumed day of ovulation. Therefore, a threshold value far pregnanedio l was sought from the database as a better marker for the end of ferti lity. A value of 1.4 mg per 24 h was not reached before day 2 after th e pre-ovulatory estrogen peak day for 96% of the cycles. In the remain ing 4% of cycles it was reached one day after the total estrogen peak day. The validity of this threshold was confirmed in extensive studies using the Ovarian Monitor where the equivalent is 6.3 mu mol per 24 h of pregnanediol glucuronide and measurements are performed on timed u rine specimens with a minimum collection time of three hours. These st udies were as follows: Ii a World Health Organization study on the use of the Ovarian Monitor as a fertility self test in the home (108 cycl es), 2) a multicenter study on returning fertility during breastfeedin g conducted by Family Health international (73 women), and 3) the gene ral application of the Ovarian Monitor for pregnancy achievement and a voidance during the past ten years (over 250, 000 PdG assays performed in ten countries). With rare exceptions, the use of these threshold v alues is applicable for all women provided correction is made for urin e volume. (C) 1998 by Elsevier Science Inc.