A female’s reproductive life begins with menarche, the first menstrual period, and ends with menopause, which is defined as cessation of menstruation for at least 12 consecutive months. The length of this reproductive period may have important implications for health. Findings of a recent report demonstrate the trend in reproductive years for females living in the United States.

The length of the female reproductive lifespan may be influenced by many factors, including access to health care, nutrition, poverty, and other environmental factors. Previous research reports that a later age of natural menopause is associated with greater life expectancy; reduced risk of cardiovascular disease, stroke, and atherosclerosis; and less loss of bone density and a reduced risk of osteoporosis and fractures. However, later natural menopause is also associated with an increased risk of breast, endometrial, and ovarian cancers.

The authors utilized data from the National Health and Nutrition Examination Survey, a large-scale survey research project that tracks the health, nutrition, and lifestyle factors of adults and children in the United States over time. The first period of data collection occurred between 1959 and 1962 and the second occurred between 2017 and 2018. From these data, the authors selected females between 40 and 74 years of age who had completed a natural menopause, meaning they did not have medical procedures that induced early menopause.

The researchers included over 7,000 females in their analysis. Between the two data periods, the average reproductive lifespan increased from 35.0 years to 37.1 years. This change was due to an increase in the average age of natural menopause (48.4 years to 49.9 years) and a decrease in the average age of menarche (13.5 years to 12.7 years). Factors that were associated with an earlier age of natural menopause and shorter reproductive lifespan included Black or Hispanic race/ethnicity, poverty, and current and former smoking status. Factors that were associated with a later age of natural menopause and longer reproductive lifespan included greater years of education and oral contraceptive use.

This research demonstrates a statistically significant lengthening of reproductive life for females in the United States; however, the impact of this longer reproductive lifespan on overall health is unknown.

• Link to full report.