New Irish-led research has demonstrated the beneficial effect that breast milk has on the heart health of premature babies.

People who are born preterm are at an increased risk of cardiovascular disorders, including ischemic heart disease, heart failure and systemic and pulmonary hypertension. They are also more likely to die as a result of cardiovascular disease.

The hearts of those born preterm are known to have unique traits, such as reduced biventricular volume, shorter length, lower systolic and diastolic function and a disproportionate increase in muscle mass.

This results in impaired heart function, which is significantly lower than that of healthy infants who are born at full term. This dysfunction is detectable at hospital discharge and persists throughout adolescence.  

However, researchers at the RCSI University of Medicine and Health Sciences studied 80 preterm infants and found that those with higher exposure to their mother’s breast milk had enhanced cardiac function at the age of 12 months, with values approaching those of healthy full-term infants.

The study found that exclusive breast milk consumption in the first months after birth is associated with a normalisation of some of the unique traits associated with preterm hearts.

Premature infants exposed to a high proportion of their mother’s own milk during the first few week after delivery had greater left and right heart function and structure with lower lung pressures and enhanced right heart response to stress at one year of age, compared to preterm infants who had a higher intake of formula, with all measures approaching those seen in full-term healthy children.

These findings were apparent before the infants were discharged from hospital and they persisted until the children were 12 months old, which was the duration of the study’s follow-up period.

“This study provides the first evidence of an association between early postnatal nutrition in preterm-born infants and heart function over the first year of age, and adds to the already known benefits of breast milk for infants born prematurely.

“Preterm infants have abnormal heart function. However, those who are fed their mother’s own milk demonstrate recovery of their heart function to levels comparable to healthy term born infants. Preterm infants fed formula do not demonstrate this recovery,” commented the study’s lead researcher, Prof Afif EL-Khuffash, clinical professor of paediatrics at the RCSI and a consultant neonatologist at the Rotunda Hospital in Dublin.

The study was carried out in collaboration with researchers at the University of Oxford; Mount Sinai Hospital, Toronto; Northwestern University Feinberg School of Medicine; Washington University School of Medicine and Harvard Medical School. Details are published in the journal, JAMA Network Open, and can be viewed here.