One hundred seventy-seven menstrual cycles in 36 women between 45 and 53 years of age were studied prospectively. All the women were experienced in the symptothermal method of natural family planning. The objective was to determine the symptothermal and hormonal indices of potential fertility by measuring urinary estrone glucuronide and pregnanediol glucuronide. Thirty-three percent had regular cycles consistent with potential fertility, 19% had cycles consistent with infertility, and 47% had a mixture of both types of cycle.
PIP: The purpose of this study of 36 climateric women with 177 cycles and symtothermal markers of potential fertility are fivefold: 1) to determine the variation in menstrual cycle length during climateric, 2) to determine daily changes in urinary hormone secretion, 3) to define criteria for potential fertility, 4) to examine the relationship between the times of clinical and hormonal changes in ovarian events, and 5) to obtain the best indicators of potential fertility during climateric. Study participants were 45-54 years old and experienced symptothermal users of natural family planning (NFP). Self reporting of vaginal bleeding, basal body temperature, cervical and cervicovaginal mucus characteristics, and climateric symptoms (hot flashes, night sweats, breast tenderness, and dyspareunia) within the past 24 hours was provided. Early morning urine samples (daily) were analyzed for estrone glucuronide (EG) and pregnanediol glucuronide (PG) by time resolved theorescence immunoassay. Each menstrual cycle was retrospectively classified as potentially fertile or infertile from the changes in daily concentrations of EG and PG. The changes were determined to be with the presence of a rise, the presence of a peak, whether it was within specified limits, the class, the number, and the %. 61% of the cycles were potentially fertile based on normal criteria for PG and EG. 33% of the women were potentially fertile, while 47% were a mixture of fertile and infertile since ovulation need not necessarily accompany normal hormonal changes. It appears that there is a gradual transition over time of changes from fertile to infertile. The cycle length and clinical indicators are useful in predicting the start and finish of a defined period of fertility as used by younger women, but further research is being conducted to develop better differentiating markers, such as the dipstick for urinary metabolites.