Abstract
AbstractPractical domestic monitoring of the menstrual cycle requires measurements of urinary metabolites of reproductive hormones: oestrone glucuronide (E1G) and pregnanediol glucuronide (PdG). Data reported in the literature are expressed as (i) concentration, without or with either creatinine- or specific gravity correction, or (ii) excretion rates. This variation in such a fundamental issue prompts consideration of the relationships between the four measures. Because the menstrual cycle kinetics of E1G and PdG are complex, we consider measurements of urinary creatinine, urea, galactose, xylose and inulin which tend to be more stable. We show that uncorrected concentration measurements of these urinary analytes can be positively correlated, negatively correlated or uncorrelated with the serum concentration. Based on measurements of urinary creatinine concentrations, urinary specific gravity and creatinine excretion rates, we conclude that urinary analyte concentration are likely to be more reliable when creatinine-corrected rather than corrected using specific gravity, but that both are less reliable than measurements of the excretion rate. This has implications for the quantitation of any urinary analyte, but especially for the monitoring of the menstrual cycle in which changes in E1G and PdG from one day to the next can be physiologically significant for a woman monitoring her fertility.
Highlights
Practical domestic monitoring of the menstrual cycle requires measurements of urinary metabolites of reproductive hormones: oestrone glucuronide (E1G) and pregnanediol glucuronide (PdG)
The concept of creatinine-correction is based on the work of Otto Folin [53,54,55] who analysed the 24 hour urines of institutionalised individuals kept on the same strict diet and fluid intake for several days
This correction has been implemented in various ways, but in each case the concentration is normalised to a function of the specific gravity (f(SG)) of the urine
Summary
Abstract: Practical domestic monitoring of the menstrual cycle requires measurements of urinary metabolites of reproductive hormones: oestrone glucuronide (E1G) and pregnanediol glucuronide (PdG). The inevitable question is whether such a difference in uA has any physiological significance In spite of these uncertainties, reports of the use of concentration measurements to monitor reproductive hormones in urine are increasingly common and in some it is claimed that specific threshold values are associated with particular events in the cycle [2, 6, 7, 30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46].
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