Research Suggests Female Fertility Declines More Rapidly Than Previously Thought, Washington Post Column Says

February 24, 2010 — It is well-documented that female fertility decreases as age advances, but new research suggests that the decline might begin much earlier and progress much faster than previously thought, Carolyn Butler writes in a Washington Post column. In a study published last month in PLoS ONE, Scottish researchers used a mathematical model to track 325 women's ovarian reserves from conception through menopause, finding that the average woman is born with about 300,000 eggs. The number of eggs steadily declines as women age, with 12% remaining at age 30 and 3% left at age 40, according to the study.

Butler writes that "it's important to remember that even 30,000 or so eggs remaining at the start of your 30s is still a lot," adding that "the quantity and quality of eggs are just two factors affecting fertility." According to the authors of the PLoS study and other experts, lifestyle factors such as being overweight, smoking and stress compound age's negative effect on fertility. Many women become pregnant "perfectly easily in their 30s and even early 40s," Butler says, noting that fertility treatments are available for those who have difficulty conceiving. "Still, given that a study published last year in the journal Fertility and Sterility found that female undergraduates significantly overestimated their fertility prospects at all ages, it seems wise for women thinking about starting a family -- or having more children -- to educate themselves about aging's effects on conception and pregnancy," according to Butler.

Claire Whelan, program director of the American Fertility Association, said, "While we may not be mature enough to conceive at a young age, nor should we, that is still when the body is most adept at conception and carrying a baby." According to Whelan, research is clear that advancing maternal age is associated with increased difficulty in becoming pregnant and increased likelihood of miscarriage; chromosomal abnormalities, such as Down syndrome; and pregnancy complications, such as gestational diabetes and hypertension. "Society has changed, but the ovaries will take another million years or two to catch up," Robert Stillman, reproductive endocrinologist with Shady Grove Fertility in Rockville, Md., said (Butler, Washington Post, 2/23).