Can a mother’s age affect a child’s intelligence? New data in the International Journal of Epidemiology says there may be a connection. In this report, first-born children of older moms (women 35 years of age or older when they had their babies) appeared to have sharper cognitive ability than kids born to younger moms (age 30 or younger).
In a survey of 40 years of data, researchers found that back in 1958 and 1970, kids 10 to 11 years old whose moms were 25 to 29 years old when they were born scored higher than children born to moms who were 35 to 39 years old. By 2001, however, the results were reversed, with the kids born to older first-time moms scoring higher on the tests. Results were similar among kids born to first-time moms who were age 40 or older, the researchers said, but pointed out that the sample size of that age group was too small for them to draw definitive conclusions.
The researchers speculate that the reversal in test scores is likely due to changing characteristics in the last several decades of women who postpone childbirth until they’re 35 years or older. They point out a greater propensity for older first-time moms to be better educated, more established in their careers, to have attained higher economic status and to be less likely to smoke. The most significant of the factors the authors cited is probably the moms’ economic status, says Dr. Nicole Scott, MD, a gynecologist and obstetrician at Indiana University Health.
“Women who have financial stability probably have a higher education status and more time to devote to raising a child,” Dr. Scott says, noting that financially secure parents are less likely to work multiple jobs and night shifts that cut down on the amount of time they can parent.
“The more financially stable you are, the more resources you have for that developing child, whether it’s having more time to read to your child or access to private schooling or good daycare,” she continues. “That all contributes to child development.”
Dr. Scott also points out that older moms have had more time to prepare for the idea of raising a baby, such as thinking about how they want to parent and what goals they have for parenting. In addition, older moms tend to have more planned pregnancies rather than surprises, “which affects how they raise their children because they were more desired,” she says.
Earlier studies similarly have noted a domino effect in how putting off childbearing appears to offer benefits to the children of those mothers, such as better general health and a greater likelihood that they’ll go to college. Because they’re more likely to have acquired more education, older moms tend to expose their children to a broader vocabulary earlier, which helps kids develop more sophisticated language skills, for example. Other research has noted that older, more established mothers are more likely to have a peer group that includes good mentors and role models for their children.
Because the average age of first-time moms has risen steady, there’s growing interest in studying the potential mental and physical health effects of waiting to have kids. In fact, the percentage of women in the US who put off having kids until they’re age 35 or older rose 23 percent between 2000 and 2014 among women in all states and across races, according to a report issued last year by the Centers for Disease Control and Prevention. So health providers need to better understand the effects maternal age has on children, the authors wrote.
Naturally, parents need to do their own risk assessment about how long to wait as well. Despite possible cognitive benefits for the children of older moms, putting off pregnancy until later in life – particularly after age 40 – comes with greater risk for health problems including pregnancy complications, birth defects and a heightened risk of diabetes and high blood pressure in their children later in life. But this and other similar studies suggest that the payoffs associated with putting off pregnancy might outweigh some of the health risks of delaying first-time motherhood.
“There are still health risks to delaying pregnancy,” Dr. Scott says. “The risk for pregnancy complications and higher blood pressure and diabetes in babies dramatically increase when mothers are above age 40. But generally, odds are that you’ll have a healthy pregnancy later in life.”
-- By Virginia Pelley