A 2009 study from researchers at Imperial College London shows that mothers under higher levels of stress put their babies at risk for developmental issues, including a lower level of cognitive development, or “baby IQ”, at 18 months. From the Imperial College London press release of the study:
Visitors to the Exhibition will have the chance to play a game that shows how a mother’s stress can increase the heart rate of her unborn baby… when the mother is stressed, the placenta becomes less protective and the mother’s cortisol may have an effect on the fetus.
The Imperial researchers’ work has shown that maternal stress and anxiety can alter the development of the baby’s brain. This in turn can result in a greater risk of emotional problems such as anxiety or depression, behavioural problems such as Attention Deficit Hyperactivity Disorder, and being considerably slower at learning. Some studies have even suggested that it may increase the likelihood of later violent or criminal behaviour. Their findings have suggested that the effects of stress during pregnancy can last many years, including into adolescence.
Professor Vivette Glover, lead researcher behind the exhibit from the Institute of Reproductive and Developmental Biology at Imperial College London, said: “We all know that if a mother smokes or drinks a lot of alcohol while pregnant it can affect her fetus. Our work has shown that other more subtle factors, such as her emotional state, can also have long -term effects on her child…
The researchers say expectant mothers should relax…
The researchers say that the stress hormone cortisol may be one way in which the fetus is affected by the mother’s anxiety during pregnancy. Usually the placenta protects the unborn baby from the mother’s cortisol, by producing an enzyme that breaks the hormone down. When the mother is very stressed, this enzyme works less well and lets her cortisol through the placenta. By studying the amount of cortisol in the amniotic fluid, the Imperial researchers’ latest study suggests that the higher the level of cortisol in the womb, the lower the toddler’s cognitive development or “baby IQ” at 18 months.
What you can do. As the study authors suggest, expectant mothers should just relax, and fathers should help them do this.
I suspect that a pre-maternity leave — or at least decreasing work-related responsibilities before maternity leave — also may alleviate some of this stress.