Children, whose mothers are diagnosed with anaemia at early pregnancy stages (before 30 weeks’ gestation period), may be at higher risk for neurodevelopmental disorders, according to research at Karolinska Institutet published in JAMA Psychiatry.
In an analysis of data on more than half a million babies born in Sweden, researchers found the risk of Autism and ADHD in children whose mothers had anaemia in early pregnancy was 44% and 37% higher, respectively, compared with those children born to mothers without early prenatal anaemia. The risk of intellectual disability was highest, at 120%.
The study doesn’t prove the anaemia causes these problems; it only shows an association. Still, said study co-author Renee Gardner and lead researcher, the findings suggest “it may be even more important than we have previously understood to boost low iron levels among women who are considering becoming pregnant or who are within the early weeks of pregnancy.”
That doesn’t mean women should panic, said Gardner, “It’s important to remember that while anaemia is common in pregnancy it’s relatively rare that otherwise healthy women receive this diagnosis before the 30th week of pregnancy.”
Anaemia is more common later in pregnancy when iron demands of the foetus increase, Gardner said.
Iron plays a role in the development of the nervous system. Gardner said: “For example, we know that it’s important for neurons making new connections with other neurons and to build the protective coating on the outside of nerve cells that improve signal transmission.
“So, while it’s possible that a lack of iron or other nutrients for a longer period of time during pregnancy directly influences the development of the brain on a molecular level, we also saw some evidence that the complications associated with anaemia, such as preterm birth and pre-eclampsia, could explain some of the increased risks that we observed.”
A diagnosis of anaemia earlier in pregnancy might represent a more severe and long-lasting nutrition deficiency for the foetus, said the doctor. “Different parts of the brain and nervous system develop at different times during pregnancy, so an earlier exposure to anaemia might affect the brain differently compared to a later exposure.”
There are other ways low iron early in pregnancy could lead to developmental problems, Gardner said in an email to Reuters.
“Babies born to mothers who were diagnosed with anaemia earlier on tended to be smaller and were more likely to be born preterm,” Gardner said. “The mothers were also more likely to have complicated pregnancies.”
While the new study shows an association between anaemia early in pregnancy, “an association is not the same as causation,” said Dr. Nevert Badreldin, an assistant professor of obstetrics and gynaecology at Northwestern University’s Feinberg School of Medicine. Women should be reassured that the current guidelines recommend screening for anaemia at the first prenatal visit, Badreldin said. “So, the great majority of women are getting screened early,” she added.
Characteristics of women with anaemia, compared with those without anaemia, included:
- Overweight and obesity
- Older age (> 40 years)
- Psychiatric history
- Higher income
- Primiparous women
- Hospitalisation for infection during pregnancy