Full-term babies born early may suffer adverse health outcomes later in life

By Kate Bass, B.Sc.Sep 29 2017

Researchers at the University of Queensland reported this week that full-term babies born just a few weeks early are more likely to have poor physical fitness throughout life compared with babies of longer gestation.

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The average human gestation period is 40 weeks, and a baby born after 37‑42 weeks is considered to be full term. It is well known that babies born pre-term, ie, before 37 weeks are prone to neurological, cognitive, and respiratory morbidity. However, with a trend towards shorter gestation periods becoming apparent, the question arose as to whether this affected the baby's health.

To address this question, data from 791 full-term babies collected in the Northern Ireland Young Hearts Study were analysed to determine whether there was an association between gestational age and cardiorespiratory fitness (a key indicator of metabolic and cardiovascular health) at age 12, 15 and 22 years. Cardiorespiratory fitness is determined by measuring maximal oxygen uptake level after undergoing standardized physical tests, which gives a measure of how efficiently the circulatory and respiratory systems supply oxygen to muscles during exercise.

Poor cardiorespiratory fitness can increase the risk of other chronic diseases, such as type 2 diabetes, metabolic syndrome and heart disease.

The analysis revealed that babies delivered between weeks 37 and 38 were 57% more likely to experience poor cardiorespiratory fitness than babies born after 39 to 42 weeks. For every additional week of gestation, the risk of poor cardiorespiratory fitness fell by 14%.

Associate Professor Isabel Ferreira from the School of Public Health said:

It is becoming increasingly evident that babies born earlier - even by only a few weeks - may face more adverse health outcomes as they get older. These could include neurological, cognitive and respiratory issues in adolescence and early adulthood".

The increasing prevalence of electively delivering babies earlier is therefore a concern. It appears that such practice is unnecessarily putting at risk the health of children.

Dr Ferreira highlighted the implications for public health policy "Health care providers and mothers should be informed of the lifelong health risks that early-term deliveries may have on babies, and refrain from these unless there is a medical reason".