These articles were first published in the American Heart Association News Website.

ORLANDO, Florida, September 16, 2016 – Two researchers at the CHU Sainte-Justine Mother-child Research Hospital and University of Montreal presented new pre-term birth studies during the American Heart Association's Council 2016 Scientific Sessions.

Preterm birth leads to smaller kidneys, higher blood pressure in adulthood

Premature birth cuts short kidney development – resulting in smaller kidneys and higher blood pressure in adulthood, according to a study.

“Adults born preterm may not present with the ‘classic’ risk factors for heart disease, but they are at increased risk of hypertension and insulin resistance and certainly require regular medical follow-up,” said Anne Monique Nuyt, M.D., senior author of the study and head of the Division of Neonatology at the Sainte-Justine University Hospital and Research Center of the University of Montreal, Canada.

Researchers compared kidney size, function and blood pressure in 40 adults born at 29 weeks of gestation or earlier to 40 adults born at full term. They found that young adults born preterm had:

• Significantly smaller kidneys relative to their body size.
• Significantly higher systolic (higher number) and diastolic (lower number) blood pressure, both on waking and averaged over 24 hours.

While the differences in blood pressure were not large — the average daily systolic blood pressure was 5 points higher in the adults born preterm (120 mm Hg) than those born full term (115 mm Hg) — the findings raise concerns about high blood pressure and heart disease risk as adults born preterm enter middle-age.

“It is well known that blood pressure will increase more markedly with aging in people who have higher blood pressures in their young adult lives than those who had lower values,” Nuyt said. “We do not know for certain whether this will be the case for individuals born preterm because the first survivors of extreme prematurity are only entering their 30s and 40s.”

Link between preterm birth, heart disease risk discovered

Abnormalities in a type of cell involved in blood vessel development and healing may explain why adults born prematurely are at increased risk of high blood pressure and other heart alterations.

Researchers at the University of Montreal compared the function of endothelial colony-forming cells (ECFCs) taken from 30 adults 21-28 years old born preterm (less than 29 weeks gestation) to 30 young adults born at term (37 or more weeks gestation). ECFCs help maintain healthy blood vessels.

Among the findings:

• Cells from preterm adults were slower to form colonies, a key step in forming new capillaries.
• Slower colony formation in preterm adults was associated with two heart disease risk factors, a higher systolic (top number) blood pressure and enlargement of the heart’s left pumping chamber.

Abnormal function of ECFCs has also been associated with early complications of preterm birth, including prolonged oxygen therapy exposure and consequent development of lung disease.