A major concern amongst older parents is the degree to which having children later in life impacts the health of their offspring. As you'll see in our course on Male Factor Infertility, fathering a child later in life confers a sightly elevated risk that child will have psychosocial or neurological challenges.
Investigators have now started to look at how having a child later in life impacts that child’s ability to conceive when they’re an adult.
Investigators looked at the history of over 50,000 women over the age of 44 to determine if there was any correlation between the age at which their mothers delivered them and the likelihood these women exited their birthing years (up to age 44) childless.
What The Study Showed:
Women born to older mothers were far more likely to exit their fertile years without a child. After adjusting for numerous confounders (education, birth order, marital status, ethnicity), women born to mothers over age 35 were nearly 40% more likely to remain childless than women born to mothers age 20 – 24.
When the investigators looked at sisters included in the study, younger sisters (born to the same, but older, mother) were more likely to be childless than older sisters (born to the same, but younger, mother). Comparing sisters of the same genepool may remove variables and strenthen the observation that the age of the delivering mother is a factor.
A major limitation in this study is that investigators only looked at whether a woman had a child, and not at her fertility per se. After all, maybe daughters of older mothers simply prefer not to have children and don't have any fertility issue.
Ultimately, the investigators recognized this and determined that 17% of daughters of older mothers reported trying to conceive unsuccessfully for over a year. This compares with only 10% of daughters born to women ages 20 – 24. Similarly, 9% of daughters of older mothers resorted to fertility pills in trying to conceive while only 6% of daughters of younger mothers did so.