Babies' early 'term' birth linked to poor respiratory fitness

SYDNEY: Babies born early in a full-term pregnancy range may be more likely to have poor cardiorespiratory fitness through adolescence and young adulthood, according to a new research study.

Cardiorespiratory fitness reflects the ability of the body to supply oxygen to muscles during physical activity and also affects metabolic and cardiovascular health throughout a person's lifetime.

The results revealed that early-term births (37-38 weeks) have nearly 57 per cent higher risk of developing poor cardiorespiratory fitness during adolescence and young adulthood. 

Each week increase in gestational age was associated with a 14 per cent risk reduction of poor cardiorespiratory fitness.

"We believe that earlier births -- even within the at-term range -- may interrupt normal development and lead to permanent changes of tissues and organs, thereby affecting cardiorespiratory fitness," said lead author Isabel Ferreira, Associate Professor at The University of Queensland in Australia. 

Importantly, these findings suggest that individuals born early-term may be at a higher risk of developing high blood pressure, Type 2 diabetes and metabolic syndrome. 

They may also be at a higher risk of suffering cardiac events in middle-age, researchers noted, in the paper detailed in the Journal of the American Heart Association.

According to Ferreira, the results should help shape policies to deter current trends towards avoidable deliveries at lower gestational ages.

"Healthcare providers and mothers should be informed of the lifelong health risks that early-term deliveries may have on their offspring and refrain from these (e.g., scheduled caesarean sections or induced labor) unless there is a medical indication to anticipate deliveries," Ferreira said.

For the study, the team examined 791 participants born within the full-term range of 37-42 weeks. Their cardiorespiratory fitness was determined at ages 12, 15 and 22 by measuring their maximal oxygen uptake level after undergoing standardized physical tests.