Children’s Long-term Health Studied in Preterm Birth Research

A study involving over 1 million children (about the population of Delaware) reveals that those born moderately preterm (32–33 weeks) or late preterm (34–36 weeks) face increased long-term risks of neurodevelopmental difficulties affecting behavior and learning. Published in the BMJ, the findings highlight the significance of these risks, as around 80% of all preterm births fall into these categories.

The research not only underscores the need for better risk assessment and follow-up for these children but also addresses a gap in understanding the long-term neurodevelopmental outcomes compared to term-born children. 

Previous research has shown that children born prematurely are at a higher risk of neurodevelopmental and behavioral challenges during their early years and throughout childhood and adolescence. However, there has been a limited number of population-based studies examining the long-term outcomes of children born moderately or late preterm compared to those born at term. 

To address this gap, researchers utilized data from the Swedish national registry, analyzing the long-term neurodevelopmental outcomes of children born at different gestational ages—specifically, those born at 32–33 weeks (moderately preterm) and 34–36 weeks (late preterm)—in comparison to those born at 39–40 weeks (full term). 

The study included 1,281,690 singleton children without birth defects born in Sweden between 1998 and 2012, ranging from 32 to 41 weeks (about 9 and a half months) of gestation. Additionally, a subgroup of 349,108 full siblings was included to control unmeasured shared genetic and environmental factors. 

The main outcomes examined were impairments related to movement (motor), brain (cognitive), epilepsy, hearing, and vision, and a combination of any neurodevelopmental impairment diagnosed up to 16. 

The analysis accounted for various potentially influential factors, including maternal age, parity, country of birth, cohabiting status, body mass index during early pregnancy, smoking during pregnancy, diabetic and hypertensive diseases, calendar period of delivery, parents’ educational level, history of neurological and psychiatric disorders, infant’s sex, and birth weight for gestational age. 

Over an average follow-up period of 13 years, 75,311 infants (48 per 10,000 person-years) received at least one diagnosis of any neurodevelopmental impairment. Specific impairments included motor impairment (5,899 cases, 4 per 10,000 person-years), cognitive impairment (27,371 cases, 17 per 10,000), epileptic impairment (11,870 cases, 7 per 10,000), visual impairment (19,700 cases, 12 per 10,000), and hearing impairment (20,393 cases, 13 per 10,000). 

Overall, when compared to children born full term, those born moderately or late preterm exhibited higher risks for any impairment. For instance, children born moderately preterm showed an additional 475 cases per 10,000 population by age 16 compared to those born full term. 

The study’s comprehensive approach sheds light on the long-term consequences of moderately and late preterm births, emphasizing the importance of considering these risks in the assessment and care of preterm infants. The findings provide valuable insights for healthcare professionals and families to better understand and address the neurodevelopmental challenges faced by children born outside the full-term range, ultimately contributing to improved care and support for this vulnerable population. 

Journal Reference  

Neurological development in children born moderately or late preterm: national cohort study, The BMJ (2024). DOI: 10.1136/bmj-2023-075630.