By Nestor Lopez-Duran PhD
Can depression during pregnancy impact your child’s intelligence? How about postpartum depression?
Maternal depression has some significant negative consequences on kids. Among them, some studies have shown that maternal depression may impact the cognitive development of the offspring. But it is still unknown how maternal depression impacts the child’s cognitive skills. For example, are there sensitive periods during the child’s early development that makes them more susceptible to maternal depression?
One could think that maybe the most important period is during pregnancy, since depression may expose the child to depression-related stress hormones that can affect the child’s early development. It is also possible that the most sensitive period is immediately after birth. For example, postpartum depression may impact the quality of mother-infant interaction during this time affecting the child’s development. It is also possible that depression during the pre-school years, a time when the child is rapidly learning complex cognitive skills, has the most negative impact on the child’s intellectual development.
The Journal of Child Psychology and Psychiatry recently published an excellent study examining this question. The study included over 5,000 families with 8-year-old children. These children completed a series of tests including a basic intellectual abilities test (IQ). The mothers of these children had completed a series of evaluations for depression during pregnancy, immediately after pregnancy, and when the child was in preschool.
The authors wanted to see if maternal depression was associated with lower IQ scores in their kids, and if so, whether this effect was due to having depression at a specific time, such as during pregnancy, immediately after birth, or during early childhood.
The results were intriguing. While adjusting for depression in all time periods, post-partum depression and depression during preschool DID NOT impact the child’s IQ at all.
The big player was depression during pregnancy!
In fact, having depression during pregnancy was associated with a drop of 3.34 IQ points by the time the child was 8 years old.
This effect was found even after controlling for a number of factors that may be associated with depression during pregnancy, such maternal age, smoking, drinking, socio-economic status, maternal education, child’s gender, child’s birth weight, and whether or not the mother breast fed the baby.
So it seems that depression during pregnancy may have a direct negative impact on the child’s intellectual development.
But why? What is it about depression during pregnancy that has such a negative impact on the child’s cognitive development?
One possibility is that depression during pregnancy exposes the child to high levels of the stress hormone cortisol, which may negatively impact the child’s brain development.
The authors also discussed another possibility: that depression during pregnancy may impact the way mothers respond to their kids after birth. That is, being depressed during pregnancy often impacts how the mother interacts with the infant once the child is born, such as by reducing the mother’s responsiveness to the infants, which in turn may negatively impact the development of the kids cognitive skills. However, if this is the case, why is it that post-partum depression did not impact the kid’s IQ, given that post-partum depression also has a significant impact on maternal behaviors, including responsiveness?
All in all, this study highlights the possibility that maternal depression during pregnancy may have a significant negative impact on the childs intellectual skills. Fortunately, we have very effective interventions for depression, so I highly recommend expecting mothers to discuss their symptoms with their physicians or health care providers and to seek a referral to a mental health provider if necessary.
For more information about depression during pregnancy I invite you to visit the University of Michigan Depression Center.
Evans, J., Melotti, R., Heron, J., Ramchandani, P., Wiles, N., Murray, L., & Stein, A. (2011). The timing of maternal depressive symptoms and child cognitive development: a longitudinal study Journal of Child Psychology and Psychiatry DOI: 10.1111/j.1469-7610.2011.02513.x