Hormones, Body Size, and Ethnicity

Abstract

The variation of reproductive hormones that characterize the menopausal transition (perimenopause) are not completely understood, particularly in non-Caucasian women. This study explored the daily patterns of reproductive hormones in a subgroup of 848 women over age 42 who were premenopausal or in the early menopausal transition and who were part of the Study of Women’s Health across the Nation (SWAN) study. Luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol (one type of estrogen) and progesterone were analyzed on a daily basis. As well, menstrual cycles were assessed for evidence of luteal activity (recall that after an egg is released, the ruptured follicle forms a structure called the corpus luteum that produces progesterone). The results of the analysis were compared to younger (mid-reproductive-aged) women who served as controls. 

• 833 complete cycles were used for study. 674 (80.9%) cycles had evidence of luteal activity, and 159 (19.1%) did not. 
• 49+ yr-old women were less likely to have cycles with luteal activity and had more variable cycle length, higher total-cycle FSH, and lower total-cycle progesterone. 
• Women with BMI (body mass index, measured in kg/m2) less than 25 (not considered medically overweight) had shorter cycles and higher total-cycle LH, FSH, and progesterone but not estradiol. 
• Chinese- and Japanese-American women had overall lower total-cycle estradiol excretion. 
• Smoking was not significantly associated with cycle length or hormones. 
• Compared to the younger women in the control group, the cycles of the women in this study had higher gonadotropins (FSH and LH), lower total progesterone, and similar levels of estradiol. This suggests that the ovary remains sensitive to elevated FSH in the early menopausal transition.