Low Birth Weight Babies and Cognitive Decline in Women

According to a study published in the June 12, 2024, online issue of Neurology, women who give birth to newborns weighing less than 5.5 pounds may be more likely than women who give birth to infants who do not have lower birth weight to experience memory and reasoning issues later in life. The impact on cognitive abilities and memory was comparable to an additional year or two of aging for individuals who had low birth weight babies.

The study does not establish a link between lower birth weight and cognitive impairments in adults. It merely displays a correlation.

“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,” said study author Diana C. Soria-Contreras, Ph.D., of the Harvard T.H. Chan School of Public Health in Boston, Massachusetts. “Our study found that a history of having a child with a lower birth weight may also be a marker of poorer cognition later in life.”

15,323 female participants in the study completed thinking and memory tests, with an average age of 62. Every participant had at least one child born to them. 1,224 individuals, or 8% of the total, had previously delivered an underweight baby. Less than 5.5 pounds was considered lower birth weight for pregnancies longer than 20 weeks.

A questionnaire regarding their pregnancy difficulties, delivery results, birth weight, and other details was filled out by the participants.

They also finished several memory and thinking exercises.

The average results of the two tests administered to assess participants’ working memory and memory, as well as their capacity to react promptly and accurately to a given scenario, were then merged by the researchers. Higher scores correlated with improved thinking and memory. For the speed and attention tests, there was an average difference of -0.06 between the groups with and without lower birth weight, and for the learning and working memory tests, it was -0.05. This is similar to the difference in this population that results from an extra year or two of age.

After adjusting for variables including age, smoking status, and high blood pressure that may have an impact on both birth weight and cognitive performance, the results were consistent. When twins or other multiple pregnancies, early births, and high blood pressure issues associated with pregnancy were excluded from the study, the findings remained the same.

Furthermore, they discovered that people’s ratings decreased with the number of low-birth-weight deliveries they experienced.

“Future research is needed to confirm our findings and to look at whether screening women with a history of low-birth-weight deliveries for cognitive issues and taking steps to promote their brain health could help prevent or delay cognitive impairment and dementia later on,” Soria-Contreras said.

The majority of the participants in the study were non-Hispanic white individuals, which limits the generalizability of the findings to other populations.

For more information: Lifetime History of Low Birth Weight Delivery and Cognitive Function in Middle-Aged Parous Women, AAN-Neurology Journals, https://doi.org/10.1212/WNL.0000000000209504