Baby Birth Weight May Indicate Your Dementia Risk, Scientists Say

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The weight of a newborn baby may be linked to the mother’s risk of dementia later in life, a study suggests.

Researchers at the Harvard T.H. Chan School of Public Health in Boston found that women whose babies are less than 5.5 pounds at birth may be more likely to have memory problems.

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Although the study does not suggest or prove that giving birth to a child with a low birth weight causes poor cognition in later life, it does show there is an association.

Study author Diana C. Soria-Contreras, a postdoctoral fellow at Harvard Medical School, said in a statement: “Previous research has shown that people who have had a low-birth-weight delivery have a higher risk of cardiovascular disease and high blood pressure. Our study found that a history of having a child with a low birth weight may also be a marker of poorer cognition later in life.”

A stock photo shows a pregnant woman. Researchers have found a link between giving birth to a low-birth-weight baby and cognitive decline later in life.

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For the study—published in the journal Neurology, the medical journal of the American Academy of Neurology—15,323 women with an average age of 62 were asked to complete a series of thinking and memory tests. All of the participants had given birth at least once.

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The women were also asked to fill in a survey about their pregnancies, including any complications, birth outcomes, and other information.

Of the group, 1,224 had given birth to a child with a low birth weight, which was defined as less than 5.5 pounds for pregnancies lasting more than 20 weeks.

They also completed a series of thinking and memory tests. Then, the team examined the test scores, as well as the participants’ ability to quickly and accurately respond to a situation. Those with higher scores had better memory and thinking abilities.

When it came to the working memory tests, there was a difference of -0.05 in the scores between people who had a low-birth-weight delivery and those who did not. For the speed and attention tests, this difference was -0.06.

Overall, the researchers found, the impact on memory and thinking ability was equivalent to one to two years of aging for people who had given birth to a low-birth-weight infant. The findings also showed that having multiple low-birth-weight deliveries lowered participants’ scores.

The researchers took into account factors that can affect birth weight and cognitive function, including the participant’s age, whether they smoked, and whether they had high blood pressure.

However, it is not known why the link between cognitive function and low birth weight may exist. Previous research has suggested that prenatal factors—such as maternal stress, infections, and diet—can affect fetal brain development and potentially influence the risk for dementia later in life.

Soria-Contreras told Newsweek: “There is insufficient research to fully understand the mechanisms behind these associations or determine if genetic factors are involved. One possible mechanism we speculate about is the presence of vascular factors in the mother.

“For example, suboptimal maternal ability to develop new blood vessels might lead to impaired fetal growth and have implications for cognitive function in the long term. This is just one potential mechanism. We will continue working to better understand these associations.”

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