Babies born late preterm at 35 weeks are at a higher risk of cardiovascular disease in adult life than those born at full term. A study 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.
The researchers looked at a pre-clinical model of late preterm birth using sheep. The sheep were given drugs to induce early labor (or allowed to give birth naturally). Sheep were followed for up to a year and then underwent extensive testing for cardiovascular and metabolic function.
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.'
In conclusion, this research has demonstrated that adult sheep, born late preterm, have evidence of Autonomic dysfunction, which may underpin the later cardiovascular dysfunction such as hypertension and increased risk of heart disease. These findings are particularly important, as late preterm infants are often assumed to escape the long-term cardiovascular morbidities known to impact very and extremely preterm offspring.
The complete research is published in Experimental Physiology.