According to a study published in the June 12, 2024, online issue of Neurology®, the medical journal of the American Academy of Neurology, people who give birth to infants weighing less than 5.5 pounds are more likely to have memory and thinking problems later in life than people who give birth to infants with a normal birth weight. For children born with low birth weight, the effect on memory and reasoning skills was similar to one to two years of aging.
The study does not establish that delivering a low-birth-weight infant affects memory and thinking issues. It just indicates a relationship.
“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,” stated study author Diana C. Soria-Contreras, PhD, from Harvard T.H. Chan School of Public Health in Boston, Massachusetts. “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.”
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
The study included 15,323 female participants, with an average age of 62 when they completed the thinking and memory tests. All participants gave birth at least once. Of the total participants, 1,224, or 8%, had a history of low birth weight. Low birth weight was defined as less than 5.5 pounds for pregnancies lasting more than 20 weeks.
Participants filled out a questionnaire on their pregnancy problems, birth outcomes, birth weight, and other details. They also took a variety of cognitive and memory tests.
The researchers then averaged the scores from two assessments of participants’ memory and ability to respond quickly and accurately to a scenario, as well as two tests of learning and working memory. Higher scores indicated improved memory and cognition. The average difference in scores between those with and without a low-birth-weight delivery was -0.06 for speed and attention tests, and -0.05 for learning and working memory. This is comparable to the difference caused by one to two more years of age in this population.
The results were similar after researchers adjusted for factors that could affect both birth weight and cognitive function, such as age, smoking status and high blood pressure. The results were also similar when researchers did not include people with premature deliveries, pregnancies with twins or other multiples or those affected by pregnancy-related high blood pressure disorders.
In addition, they found that the more low-birth-weight deliveries people had, the lower their scores were.
“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,” according to Soria-Contreras.
The study’s weakness is that the majority of the participants were non-Hispanic white people, so the findings may not be applicable to other populations.
The study was funded by the National Institute of Mental Health, the National Institute of Environmental Health Sciences, the National Institute on Aging, and the Office of Research on Women’s Health.
