Urinary estrogen and progesterone metabolite concentrations in menstrual cycles of fertile women with non-conception, early pregnancy loss or clinical pregnancy.

BACKGROUND Knowledge is limited of how estrogen and progesterone variability in fertile women are associated with achieving pregnancy. METHODS From 1996 to 1998, we enrolled 347 textile workers without hormone treatment in Anhui, China, who provided daily urine and data upon stopping contraception for up to 1 year until clinical pregnancy. Urinary hCG was assayed to detect conception and early pregnancy losses. We compared urinary concentrations of estrone conjugates (E(1)C) and pregnanediol-3-glucuronide (PdG) in 266 clinical pregnancies, 63 early pregnancy losses and 272 non-conception cycles from 347 women and also in 94 clinical pregnancy and 94 non-conception cycles from the same women. RESULTS Using generalized estimating equations and relative to 266 clinical pregnancy cycles, log(E(1)C) was lower in 272 non-conception cycles [beta = -0.3 ng/mg creatinine (Cr); SE = 0.1; P < 0.0001]. On average, daily E(1)C was 18 ng/mg Cr lower in non-conception cycles than in clinical pregnancy cycles. Relative to 94 clinical pregnancy cycles, log(E(1)C) was lower in 94 non-conception cycles (beta = -0.4 ng/mg Cr; SE = 0.1; P < 0.0001) from the same women (average difference in daily E(1)C was 20 ng/mg Cr). The odds of E(1)C less than the 10th percentile (<30 ng/mg Cr) were higher in early pregnancy loss cycles [odds ratio (OR) = 4.8; P = 0.0027] than in clinical pregnancy cycles in the early luteal phase. Compared with clinical pregnancy cycles, log(PdG) concentrations were lower in non-conception cycles during the follicular phase, but this analysis lacked power for multiple testing. CONCLUSIONS Estrogen concentrations varied from cycle to cycle, and higher estrogen was associated with achieving clinical pregnancy.