Objective: To examine hormonal predictors of conception in menstrual cycles from normal women.
Design: Longitudinal study.
Patient(s): Two hundred fifteen healthy female volunteers with no known fertility problems who were trying to conceive.
Intervention(s): Participants recorded menstrual bleeding, sexual intercourse, and collected first morning urine specimens daily from when they stopped contraception until they became pregnant or for 6 months if no clinical pregnancy was achieved. Measurements were made of urinary LH and urinary metabolites of estrogen and progesterone.
Main outcome measure(s): Conception was identified by a sensitive and specific immunoradiometric assay for urinary hCG.
Result(s): Statistical analyses of 189 conception and 409 nonconception cycles controlled for sexual intercourse and interdependence of cycles from the same woman. Conception was more likely in cycles with lower baseline progesterone metabolite levels, higher ovulatory LH, and higher midluteal progesterone. Midluteal estrogen also was elevated in conception cycles when examined without adjusting for other hormone levels, but this finding did not persist after multivariate adjustment.
Conclusions: Menstrual cycles in normal women vary in their hormonal quality in ways that are predictive of cycle fertility.