Delaying pregnancy: can we test how fast the biological clock is ticking?



As women increasingly wait to start families, the age of first birth is rising in the United States. As a result, the well-documented decrease in female fertility with age can leave some women unable to conceive when they are ready. Fertility clinics commonly use biomarkers to assess the number of eggs a woman has remaining, known as ovarian reserve, and thus predict fertility. If a similar technique could be used to predict fertility in the general population, it might be very helpful for reproductive planning — and some products are on the market already with the assumption that those biomarkers are useful.


IRP investigator Donna D. Baird, Ph.D., and collaborators undertook a prospective study of time to pregnancy among 750 women aged 30 to 44 who wanted to conceive. Levels of several reproductive hormones in the women’s blood and/or urine, including anti-Müllerian hormone and follicle stimulating hormone (FSH), failed to predict fertility.


This study showed that, among women in their later reproductive years attempting to conceive naturally, biomarkers of ovarian reserve are not useful predictors of fertility. The findings do not support the use or marketing of urinary or blood follicle stimulating hormone tests or anti-Mϋllerian hormone levels to assess natural fertility in the general population.


Steiner AZ, Pritchard D, Stanczyk FZ, Kesner JS, Meadows JW, Herring AH, Baird DD. (2017). Association between biomarkers of ovarian reserve and infertility among older women of reproductive age. Journal of the American Medical Association. Oct 10;318(14):1367-1376.

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This page was last updated on Tuesday, June 13, 2023