Moderate Preterm Birth Linked to Cognitive Deficits in Childhood in New Study
Children born before 34 weeks of gestation exhibited significant cognitive deficits by age 9-10, independent of genetic and socioeconomic factors, reported researchers.
A new study published in JAMA Network Open sheds light on the lasting cognitive effects of preterm birth, revealing that children born moderately preterm (32-33 weeks gestation) exhibit significant cognitive deficits by the age of 9 or 10. These effects remain even after accounting for genetic factors, socioeconomic status (SES), and other prenatal and postnatal influences.
The study, part of the Adolescent Brain and Cognitive Development (ABCD) Study, followed 5946 children aged 9 to 10 years, with a diverse demographic that included 51.8% male participants. A team of researchers from the Karolinska Institute used a comprehensive neurocognitive assessment battery, including tools like the NIH Toolbox and the Rey Auditory Verbal Learning Test, to measure cognitive outcomes in areas such as vocabulary, working memory, attention, and episodic memory.
Among the children studied, 0.9% were born very preterm (28-31 weeks), 1.8% moderately preterm (32-33 weeks), 7.6% late preterm (34-36 weeks), 4.4% early term (37-38 weeks), and 85.2% were born full-term (≥39 weeks). Researchers found that children born moderately preterm scored significantly lower than full-term peers across several cognitive domains, including vocabulary (β = −0.36), working memory (β = −0.27), and episodic memory (β = −0.32), with all results showing statistical significance (P < .001).
In contrast, children born late preterm and early term performed similarly to full-term children in most cognitive areas, suggesting that the cognitive risks associated with preterm birth may be more pronounced in those born before 34 weeks of gestation.
The study utilized a polygenic score for cognitive performance (cogPGS) to account for genetic influences. Results showed that genetic factors did not fully explain the cognitive differences observed in moderately preterm children. The polygenic score was positively associated with higher cognitive scores (β = 0.14; P < .001), but the effect size for moderate preterm birth was much larger (β = −0.39; P < .001), highlighting the independent impact of preterm birth on cognitive development.
Results from the study also indicate that the lowest cognitive scores were observed in children born at 32 weeks gestation or earlier. These children showed specific deficits in vocabulary, working memory, episodic memory, short- and long-delay recall, and visuospatial skills. Interestingly, children born at 33 weeks did not exhibit significant cognitive differences from full-term children, indicating that the cognitive risks might become more pronounced at 32 weeks or earlier.
Additionally, the study explored whether neonatal characteristics, such as the need for respiratory support or breastfeeding duration, mediated the association between preterm birth and cognitive outcomes. However, these factors did not significantly influence the observed cognitive deficits, reinforcing the idea that preterm birth itself is a key risk factor.
The research team also conducted sensitivity analyses to rule out the influence of children with intellectual disabilities or attention-deficit/hyperactivity disorder, which might confound the results. These analyses confirmed that the observed cognitive differences in moderately preterm children remained significant even after excluding these factors.
The study's findings suggest that the cognitive challenges faced by children born moderately preterm are independent of other risk factors like genetics and SES, underscoring the importance of early interventions. The authors recommend that health care professionals pay particular attention to children born before 34 weeks gestation, as they may be at greater risk for cognitive delays and learning difficulties as they progress through school.
“Given these findings, longer-term follow-up of children born before 34 weeks is warranted, as they may face increased developmental challenges that require more complex cognitive functioning at older ages,” concluded investigators.
Reference: Nivins S, Padilla N, Kvanta H, Ådén U. Gestational age and cognitive development in childhood. JAMA Netw Open. Published online April 14, 2025. doi:10.1001/jamanetworkopen.2025.4580
