Harmful exposures during pregnancy, including some that occur even before pregnancy is recognized, appear to dramatically increase a child’s risk of psychiatric or behavioral problems early in life, researchers from Massachusetts General Hospital report.
In their study of 9,290 children aged 9 to 10 living in 21 communities in the United States, the researchers found that children subjected during pregnancy to at least two of six adverse exposures were significantly more likely to have high scores. clinically significant in the child. Behavioral Checklist (CBCL), indicating a higher level of problems such as depression, attention difficulties or anxiety.
Adverse prenatal exposures are unplanned pregnancies; maternal use of alcohol, tobacco or marijuana before pregnancy is recognized; complications during pregnancy (such as high blood pressure or gestational diabetes); and complications during labor and delivery. Premature or cesarean delivery was not associated with an increased risk.
“Although these factors have been individually associated with similar risks in previous, often smaller studies, this is the first time we have been able to assess the effect of cumulative exposures, which were quite dramatic,” says the senior author Joshua L. Roffman, MD, MMSc, director of the Mass General Early Brain Development Initiative.
For example, while children with none of the exposures during their mother’s pregnancy had only a 7% chance of developing clinically significant psychiatric symptoms, this risk increased sharply and in a linear fashion, so that those with four or more exposures had a 29% chance of clinically significant symptoms.
As the researchers report in their study, published in the open access journal PLOS ONE, they saw similar trends across a range of specific symptoms, from mood and anxiety to attention and thinking disorders.
Associations between prenatal exposures and psychiatric symptoms in childhood were maintained even when researchers took into account other factors that could skew the results, such as the socioeconomic status of the mother, or postpartum exposures that are known to increase a child’s risk of suffering from psychiatric disorders, such as as a traumatic life event.
To validate their results, Roffman and his colleagues also tested them in a separate group of non-twin siblings who differed in their exposures during pregnancy, and here too the data showed that the brother with the most exposures was at higher risk for symptoms.
One limitation of the results is that they are based on the mother’s recollection of events during pregnancy, although the frequency of adverse events closely followed national trends. The study did not measure the effects of maternal infections or stress during pregnancy, although each of these was also associated with increased risk in previous studies.
Given the additive effects of the common exposures they studied, Roffman and his colleagues believe that the “floor” of risk for psychiatric symptoms may have been increased for children born during the COVID-19 pandemic.
“Our results reinforce the importance of the prenatal environment for brain health and reducing the risk of psychiatric symptoms in childhood. This increases the urgency of the need to discover, develop and implement early interventions that mitigate some of these risks, ”says Roffman, who is also an associate professor of psychiatry at Harvard Medical School (HMS).
Improving children’s brain development and psychiatric health is the main goal of the Mass Early Brain Development Initiative, a multidisciplinary collaboration between staff from the departments of psychiatry, obstetrics, pediatrics and medicine.