50 years later, preterm babies do not have significantly worse health outcomes

Key takeaways:

• People born preterm were more likely to report having high blood pressure than those born at term.
• They had a lower risk of experiencing a major adverse cardiovascular event.

After 50 years of life, people who were born preterm had lower odds for some cardiovascular outcomes and similar odds for most other health outcomes compared with those born at term, according to a study published in Pediatrics.

This study is a follow-up to the Auckland Steroid Trial, in which pregnant women at risk for preterm birth received antenatal corticosteroids between December 1969 and February 1974 at National Women’s Hospital in Auckland, New Zealand. Researchers followed the health outcomes of the 1,218 children born during the trial 30 and 50 years later.

Anthony G.B. Walters, MBChB, a doctoral candidate at the Liggins Institute at the University of Auckland, and colleagues surveyed 424 living participants (mean age, 49.3 years; 47.7% female) and also included 46 participants who died after age 1 year. More than two-thirds (69.4%) of the participants included in the follow-up were born before 37 weeks’ gestational age.

The primary outcome was at least one cardiovascular event, like stroke or heart attack, or a cardiovascular risk factor like diabetes or hypertension. The researchers also looked at secondary outcomes related to respiratory, mental health and educational status.

They found that a slightly larger proportion of people born preterm had at least one primary outcome compared with those born at term, but the difference was not statistically significant. However, when they adjusted for socioeconomic status, participants born preterm were significantly more likely to experience a cardiovascular event or risk factor (aRR = 1.44, 95% CI, 1.04-1.99).

They did find that the risk for a major adverse cardiovascular event was lower among preterm participants compared with term participants, 2.8% vs. 6.9% (aRR = 0.33; 95% CI, 0.14-0.79). Preterm participants were older at their first hospital admission for a major adverse cardiovascular event (aHR = 0.31; 95% CI, 0.12-0.79).

Participants who were born preterm were more likely to report having high blood pressure vs. those born at term (aRR = 1.74; 95% CI, 1.16-2.61). The odds for other cardiovascular risk factors were similar in both groups.

“Hypertension is the cardiovascular risk factor with the most well-established relationship with preterm birth,” Walters and colleagues wrote. “Our finding ... is consistent with these reports and also previous findings from this cohort of higher systolic blood pressure at 30 years compared with those born at term.”

Participants born preterm were significantly less likely to have any mental health disorder (aRR = 0.73; 95% CI, 0.59-0.92) or depression (aRR = 0.74; 95% CI, 0.56-0.99) than those born at term. They were also less likely to have hearing difficulty (aRR = 0.2; 95% CI, 0.05-0.71).

When the researchers adjusted the odds of primary outcomes for BMI, there was no significant difference between the preterm and at-term birth groups.

Walters and colleagues found no significant differences between preterm and term participants for BMI, chronic kidney disease, death from any cause after age 1 year, respiratory outcomes, self-reported general health or educational outcomes.

“Since the outset of the field decades ago, neonatology has been criticized for advancing survival rates at the cost of comorbid illness and quality of life,” Jonathan S. Litt, MD, MPH, ScD, associate professor of pediatrics at Stanford Medicine, and Henning Tiemeier, MD, PhD, Sumner and Esther Feldberg Professor of Maternal and Child Health at Harvard T.H. Chan School of Public Health, wrote in a related editorial. “[This study] shows that those fears may have been misplaced.”

“The fatalistic premise that gestational age alone determines future health risk is challenged by the breadth of outcomes observed among surviving preterm infants,” they wrote.

References:

• Litt JS, et al. Pediatrics. 2024;doi:10.1542/peds.2024-068441.
• Walters AGB, et al. Pediatrics. 2024;doi:10.1542/peds.2024-066929.