Babies born late preterm may be at risk of cardiovascular diseases

02 November 2017. Babies born late preterm at 35 weeks are at a higher risk of cardiovascular disease in adult life than those born at full term, according to research published in Experimental Physiology.

Researchers from Hudson Institute of Medical Research and Monash University, Australia found that lambs born preterm were more likely to show altered control of the heart by the part of our nervous system under subconscious control (sympathetic and parasympathetic nervous system).

Young adult females of late preterm birth were more likely to have decreased sympathetic nervous system activation of the heart. This is an early marker of cardiovascular disease, and it occurred in otherwise healthy lambs. In males, the results were different; adult premature males didn’t have the innate reflexes that normally bring their blood pressure back to normal when it gets too low or too high. 

Researchers looked at a pre-clinical model of late preterm birth using sheep. The sheep were given drugs to induce early labour (or allowed to give birth naturally). Sheep were followed for up to a year and then underwent extensive testing for cardiovascular and metabolic function.

Further research into the organs of these animals is being carried out to see if changes to these could have contributed to the results observed.

Corresponding author Dr Beth Allison said:

‘Importantly, these lambs were not born very premature; they were the equivalent of 35 week human babies.  Infants born at this time are generally considered very low risk for morbidity and mortality after birth.’


Notes for Editors

  1. Sheep in the preterm group were given betamethasone, a drug which is routinely given to all threatening preterm births to rapidly mature the lungs. Sheep in the control group were not given betamethasone. This is a limitation as betamethasone itself is known to have dramatic effects on cardiovascular function. However, human preterm  infants will receive betamethasone as standard clinical care, making this experimental paradigm reflective of the human clinical population and these results and the conclusions are still appropriate and important for mildly premature infants
  2. The effect of sex and prematurity on the cardiovascular baroreflex response in sheep:
  3. Experimental Physiology publishes advances in physiology which increase our understanding of how our bodies function in health and disease. 
  4. The Physiological Society brings together over 3,500 scientists from over 60 countries. The Society promotes physiology with the public and parliament alike. It supports physiologists by organising world-class conferences and offering grants for research and also publishes the latest developments in the field in its three leading scientific journals, The Journal of Physiology, Experimental Physiology and Physiological Reports. 


The Physiological Society: 
Julia Turan, Communications Manager 
+44 (0)20 7269 5727 

Corresponding author:
Beth Allison, PhD