Factors Related to Declining Luteal Function in Women During the Menopausal Transition

Abstract

The Daily Hormone Study (DHS) is a sub-study of SWAN, the Study of Women's Health Across the Nation. It enrolled 848 women presenting at ages 43-53 years, who collected daily urine specimens for a single cycle or for up to 50 days a year for as long as 3 years. The investigators hypothesized that luteal function would decline as women progressed through the menopausal transition (MT), and they sought to identify those features previously linked with reproductive hormones in the SWAN that are associated with declining luteal function. The proportion of ovulatory-appearing cycles decreased from 81% at baseline to 65% by the third DHS assessment (H3). The frequency of cycles presumed to be anovulatory and not ending with bleeding by 50 days increased from 8% to 24% during the same interval, and were associated with progress to early or late perimenopause, African-American ethnicity, and less than a high school education. The frequency of anovulatory cycles ending with bleeding continued to be about 10% from baseline to H3. When compared with ovulatory cycles, they were associated with obesity and more than a high school education. Serum estradiol levels in the highest and lowest categories were associated with anovulatory/non-bleeding cycles. Levels of pregnanediol glucuronide declined by about 7% for each year of study. Measures of insulin sensitivity were not strongly associated with menstrual cycle hormone concentrations. The investigators believe that, based on these findings, anovulation without bleeding signifies progression through the MT. Declining luteal progesterone excretion in ovulatory cycles also points to progress through the MT. Anovulation with bleeding intervals of fewer than 50 days appears not to be associated with progress through the transition.