Breast Milk Linked to Better Heart Health in Premature Babies

Marisa Wexler MS avatar

by Marisa Wexler MS |

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For premature babies who are at high risk of pulmonary hypertension (PH) and other cardiovascular complications, consuming human breast milk in the first year of life is associated with better heart function, a new study found.

“Preterm infants have abnormal heart function,” Afif EL-Khuffash, MD, the study’s lead author, said in a press release. “However, those who are fed their mother’s own milk demonstrate recovery of their heart function to levels comparable to healthy term born infants.”

Such improvement can help reduce the risk of PH and other problems.

“Preterm infants fed formula do not demonstrate this recovery,” said EL-Khuffash, a professor of pediatrics at the Royal College of Surgeons in Ireland.

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According to the researchers, this result “supports the use of human milk to diminish long-term cardiovascular disease risk in individuals who were born preterm.”

“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,” EL-Khuffash said.

The findings were published in the journal JAMA Network Open, in a study titled “Cardiac Performance in the First Year of Age Among Preterm Infants Fed Maternal Breast Milk.”

Infants born preterm, or before 37 weeks of pregnancy, are at an increased risk of heart-related health complications, research has shown. Many babies born prematurely, especially those born earlier on in pregnancy, show alterations such as lower heart function and a disproportionate increase in cardiac muscle mass later in life.

Now, an international team of researchers analyzed data collected in a clinical trial (NCT01435187) to assess whether consuming breast milk — as opposed to formula — might enhance heart health in babies born early.

The team analyzed data for 80 babies born preterm between 2011 and 2013. The infants were born after a median of 27 weeks of gestation — for context, a typical pregnancy lasts about 40 weeks. Among the preterm babies, 54% were Black, and the same proportion was female.

Using a battery of statistical analyses, the researchers looked for significant associations between various measures of heart function, and the number of weeks that the infants had been exposed to breast milk, or their mother’s own milk (MoM). The team focused on outcomes at one year corrected age — obtained by subtracting the number of weeks or months a baby was preterm to his or her actual age.

The results showed that increased MoM consumption was associated with better function of both the right and left ventricles at one year corrected age. The right ventricle (RV) is the part of the heart that pumps blood to the lungs to pick up oxygen; the left ventricle (LV) then pumps this oxygen-rich blood to the rest of the body.

More weeks of MoM consumption also were significantly associated with lower pulmonary vascular resistance, which evaluates the internal resistance to blood flow within the pulmonary arteries.

Further analyses showed that infants who had less than about one month of breast milk were significantly more likely to have LV and/or RV impairment, or abnormally high pulmonary blood pressure.

“Preterm infants exposed to more MoM during the early neonatal period had greater LV and RV function and structure with lower pulmonary pressures … at age 1 year, with all measures approaching those seen in controls born full-term,” the investigators concluded.

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Notably, a separate analysis that looked at babies who were given donor human milk (breast milk from someone other than their biological mothers) found some evidence that donor milk improved RV function, but showed no evidence that donor milk improved LV function or lessened lung blood pressure.

As to the benefits of donor milk over exclusive formula feeding, the scientists said that although pasteurization markedly reduces the bioactive properties of human milk, it does not completely destroy them. The team noted, however, that exactly what compounds in breast milk might improve heart health remains an area that needs further investigation.

The researchers said their findings support the use of breastfeeding, especially in the first year, and said mother’s own milk “may play a role in mitigating adverse cardiac programming during early life” for premature babies.

“This study found that preterm infants with higher consumption of mother’s own milk had enhanced cardiac performance at age 1 year, suggesting that mother’s own milk consumption may play a dynamic modulator role on cardiac mechanics,” they wrote.

The scientists stressed that, because this study only looked for correlations or statistical associations, it is impossible to definitively conclude a cause-and-effect relationship between breast milk consumption and heart health based on the data. Other factors likely contribute, they said.

For example, the team noted that white babies were given MoM more frequently than their Black counterparts, and there are well-established disparities in many healthcare outcomes based on race.