Average reproductive lifespan in women has increased by 2 years, study finds

A recent study found that the average reproductive lifespan for women in the United States is appearing to increase. 

Researchers studied trends in the age of natural menopause in women as well as reproductive lifespan in conjunction with other societal factors using data from the past 60 years. 

The study was published April 6 in the medical journal JAMA. Scientists say they found trends pointing to increased age of natural menopause in the United States hinting that the age when women can get pregnant without experiencing medical issues is increasing. 

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The U.S. Centers for Disease Control and Prevention explains that women experience menopause usually between 45 and 55 years of age. At that point, menstruation ceases, marking the end of a woman’s natural reproductive cycle. 

Researchers in the April study analyzed data from nearly 10,000 women. They said that "overall, from 1959-1962 to 2015-2018, the mean age at natural menopause increased from 48.4 years to 49.9 years. 

While menopause occurs for some women as early as age 45, the average reproductive lifespan has hovered at 35 years. But researchers found the average reproductive cut-off age increased by two years.

"Over this interval, the mean reproductive life span increased from 35.0 years to 37.1 years," study authors wrote. 

There have been some rare cases recorded in which some women have been able to give birth well into their fifties. 

In March, a New Hampshire woman who lost her 13-year-old daughter to a brain tumor in 2016 was able to give birth to a son at the age of 57. Higgins gave birth to a healthy boy named Jack. He weighed 5 pounds, 13 ounces. "Yes, I’m scared and I’m anxious, but I’m so excited," Higgins told the Concord Monitor.

Study author Duke Appiah, Ph.D., MPH, a cardiovascular epidemiologist at Texas Tech University, said his team’s findings could help them better understand how increased reproductive lifespan in women might impact health issues including heart disease and cancer in women. 

"If you have a shorter reproductive lifespan you are more likely to get diseases like osteoporosis, diabetes and other neurological disorders," Appiah explained. "However, if you have a longer period, you have greater exposure to endogenous estrogens and that has been associated with some cancers like breast cancer and ovarian cancer," he added. 

Appiah says his team has not specifically looked at correlations between reproductive lifespan and cancer, but his work has found relationships between reproductive lifespan and diabetes. 

He explains that a shorter reproductive lifespan is associated with higher risks for type two diabetes. He has also found that earlier age menopause has been associated with heart failure and other cardiovascular issues. 

Despite some of the health risks associated with early menopause and late reproductive activity in women, giving birth later in life is becoming increasingly more common in the U.S. The CDC estimated that since 2007, the birth rate has risen 19% for women in their early 40s. 

Appiah says he hopes his findings will influence guidelines based on empirical evidence that will allow women to better understand their own reproductive health.