Individuals whose mothers were hospitalized for an infection during pregnancy are at greater risk for autism and depression, according to a new Swedish study of nearly 1.8 million children.
“The results indicate that safeguarding against and preventing infection during pregnancy as far as possible by, for instance, following flu vaccination recommendations, may be called for,” said Dr. Verena Sengpiel, associate professor of obstetrics and gynecology at Sahlgrenska Academy, University of Gothenburg in Sweden.
The findings are published in the journal JAMA Psychiatry.
Maternal infection with certain infectious agents, such as cytomegalovirus (CMV) or the herpes virus, are already known to be capable of harming fetal brain development and increasing the risk of certain psychiatric disorders.
The new findings, however, add to this knowledge by revealing that infection in general during pregnancy, too — including when the actual infectious agent does not reach the fetal brain — is linked to a greater risk of the child developing autism or depression later in life.
The researchers studied data on all children, totaling almost 1.8 million, born in Sweden during the years 1973-2014. The particulars from the Swedish Medical Birth Register were linked to the national inpatient register, which records whether the mother was treated in hospital with an infection diagnosis during pregnancy.
Using the inpatient register, the researchers also monitored these children’s mental health until 2014, when the oldest were aged 41.
The results show that if, during pregnancy, a mother with an infection diagnosis received hospital treatment, there was a significant increase in the risk of her child needing hospital care later in life, with a diagnosis of either autism or depression. The increase in risk was 79 percent for autism and 24 percent for depression.
No link was found between the mothers being in the hospital with an infection diagnosis during pregnancy and two other psychiatric diagnoses studied in their children: bipolar disorder and psychosis, including schizophrenia.
The pregnant women in the study may have been hospitalized with diagnoses other than infections, but then had infections diagnosed during their stay as well. The heightened risk of mental ill-health in the child was also evident after infections in their mothers that are usually considered mild, such as a common urinary tract infection.
The study was observational and offers no answer on how maternal infection during pregnancy impacts fetal brain development. However, other research has shown that an infection in the mother leads to an inflammatory reaction, and that some inflammatory proteins can affect gene expression in fetal brain cells.
Other studies have also found that inflammation in the mother increases production of the neurotransmitter serotonin in the placenta, which may affect fetal brain development.
Source: University of Gothenburg