High levels of stress during the third trimester of pregnancy linked to lower IQ in male children, research shows
- One study found that male children of stressed mothers tended to have lower IQs
- This may be due to exposure to high levels of the stress hormone cortisol
According to a new study, stress during the third trimester of pregnancy can lead to lower IQ in male children.
When women are pregnant, their levels of cortisol – a steroid hormone released in response to stress – naturally increase.
It is necessary for the healthy development of a baby and has a positive influence on the development of his brain.
However, researchers have found that excessive levels of the hormone during the last three months of pregnancy can hinder IQ scores in boys as young as seven years old.
To investigate its effect on cognitive function in children as they grow, researchers analyzed data on the cortisol levels of 943 pregnant women during their third trimester and their children’s IQ tests at age seven.
Experiencing high levels of stress during the third trimester of pregnancy may be linked to lower IQ in male babies, according to a new study (file photo)
They found that pregnant women carrying a boy had lower blood cortisol levels than women carrying a girl.
However, boys exposed to higher cortisol levels in the womb scored lower on IQ tests at age seven.
Girls, on the other hand, didn’t seem to be bothered by it.
The researchers from Odense University in Denmark say their findings suggest boys are ‘more vulnerable to prenatal exposure’ to cortisol than girls.
A previous study conducted by the same research team found that children between the ages of one and three years have more advanced speech and language skills when their mothers have high cortisol levels during their third trimester.
That study found that boys born to mothers exposed to high levels of stress were able to say more words at ages 12 to 37 months, while girls were able to understand more words at ages 12 to 21 months.
Researchers found that children whose mothers had experienced high levels of stress tended to exhibit lower IQs at the age of seven (file photo
Lead author Dr Anja Fenger Dreyer said: ‘Although our previous study found that prenatal cortisol exposure was positively associated with language development, in this study prenatal cortisol exposure was negatively associated with IQ scores.
‘This may mean that high levels of prenatal exposure can have a temporary effect on a child’s cognitive development.
‘It should also be noted that vocabulary in toddlers in our previous study was reported by parents, while child IQ in this study was assessed by trained psychologists.’
Separate research has also found that babies exposed to high levels of cortisol are more likely to develop behavioral problems and stress-related illnesses later in life.
Meanwhile, experts have previously suggested that women who are stressed at the time of conception are twice as likely to have a girl.
The findings were presented at the European Congress of Endocrinology in Stockholm.