TOTAL URINARY FOLLICLE-STIMULATING-HORMONE AS A BIOMARKER FOR DETECTION OF EARLY-PREGNANCY AND PERIIMPLANTATION SPONTANEOUS-ABORTION

Total concentrations of follicle stimulating hormone (FSH) were evalua ted in daily urine samples from conceptive and nonconceptive menstrual cycles by measurement of the FSH beta subunit following treatment of the samples to dissociate the FSH heterodimer. Samples were self-colle cted by normal subjects during cycles in which daily blood samples als o were obtained. Daily blood and urine specimens were collected prospe ctively from 10 subjects in conceptive cycles, which led to normal pre gnancies, and from 10 subjects with bilateral tubal ligations to provi de control samples from nonconceptive cycles. Mean serum and urinary F SH concentration profiles were parallel in both groups following ovula tion and during the first 9 days of the luteal phase. Mean values for both serum and urinary FSH rose significantly above the postovulatory baseline by 10-12 days following the midcycle luteinizing hormone (LH) peak in nonconceptive cycles, but did not rise at any time following ovulation during conceptive cycles. Following regression analysis of t he changing FSH concentrations between days 9-14 post-LH surge in conc eptive cycles, a slope of less than or equal to 0.02 ng FSH/mg creatin ine/day was selected as a cutoff point to identify conceptive cycles. There was a high concordance between the day of LH peak in serum and t he day of FSH peak in urine. Therefore, in applying the algorithm, the day of FSH peak in urine was used to determine the days for which the FSH slope would be calculated, i.e., days 9-14 post-FSH peak in urine . The sensitivity and specificity of the change in urinary FSH concent rations to detect pregnancy in a different set of 55 cycles were found to be 88.9% and 89.3%, respectively. All six cases of early fetal los s in the sample set were correctly identified. These results suggest t hat urinary FSH can be used as an additional biomarker for the verific ation of early pregnancy in prospective epidemiologic studies in which early fetal loss is a suspected outcome.