OVULATION PREDICTION - CHANGES IN THE CONCENTRATIONS OF URINARY ESTRONE-3-GLUCURONIDE, ESTRADIOL-17-BETA-GLUCURONIDE AND ESTRIOL-16-ALPHA-GLUCURONIDE DURING CONCEPTIONAL CYCLES

The concentrations of estrone-3-glucuronide (E1-3-G), estradiol-17.beta.-glucuronide (E2-17.beta.-G), estriol-16.alpha.-glucuronide (E3-16.alpha.-G) and luteinizing hormone/human chorionic gonadotropin were measured in daily samples of early morning urine from 6 women who conceived during the period of study. The specimens were collected from the 2nd day of menstruation until the values for hCG were > 200 U/l. The aim of the study was to assess which of the metabolites should be measured preferentially to predict ovulation by 72 h and hence identify the probable start of the fertile period. The peak of LH was used as a reference point for ovulation and defined as day 0. A defined rise (50% increase over the mean of 3 preceding values) in the concentration of each steroid metabolite occurred on the following days (mean and range); E1-3-G day LH-4.7 (-3 to -6), E2-17.beta.-G day LH-3.7 (-3 to -6) and E3-16.alpha.-G day LH-4.5 (-3 to -6). The concentration (nmol/l; mean and range) of each metabolite on the day of the rise was: E1-3-G (106; 78-137), E2-17.beta.-G (19; 5-27) and E3-16.alpha.-G (28; 18-40). Evidently, the measurement of each estrogen glucuronide provides similar information; quantitatively E1-3-G is the most important.