A Steroid for Premature Babies' Lungs: What Happened by the Time the Children Reached School

A large U.S. study followed children who, as very premature newborns, received hydrocortisone or a placebo — and checked how they were doing at ages 5 to 7

A large American study followed very premature babies who had been given a steroid called hydrocortisone, or a dummy treatment, to protect their fragile lungs — and then measured how those same children were doing when they reached early school age. The steroid made no difference, good or bad, to how the children were thinking, moving, learning, or exercising at ages 5 to 7. The more sobering finding was that nearly three out of four of these children, who had all been very sick newborns, had some kind of developmental difficulty by school age, whether or not they had received the steroid [1].

Why This Question Matters

Babies born very early — here, before 30 weeks of pregnancy, when a full pregnancy is about 40 weeks — often have lungs that are not ready to breathe on their own. Many need a breathing machine, called a ventilator, for days or weeks. When that lung trouble drags on, doctors call it bronchopulmonary dysplasia, or BPD: a chronic lung disease of prematurity. BPD is the most common serious complication these tiny babies face, and it is not just about breathing in the hospital. Children who had BPD are more likely to have later difficulties with thinking, movement, and lung health, and their care places real demands on families and the health system [2][3]. Even today, with all the advances in newborn care, a large share of the most premature babies still develop BPD, so doctors keep searching for something that safely prevents it [4].

How Families and Doctors Used to Face This

For many years, the main tool against BPD was a powerful steroid called dexamethasone. It did help the lungs. But when researchers followed those children as they grew, they discovered a painful trade-off: dexamethasone, especially when given very early, was linked to a higher risk of cerebral palsy and developmental problems. The medical community pulled back sharply, and steroid use swung back and forth over the years as doctors tried to weigh lung benefit against brain risk [5][6]. That history is the reason every steroid decision in a premature baby is made so carefully.

Doctors then turned to hydrocortisone, a gentler steroid that more closely resembles a hormone the body makes naturally, hoping it might protect the lungs without harming the developing brain. Some earlier research suggested it might even help development a little [7]. To test this properly, a large network of U.S. hospitals ran a careful experiment: 800 very premature babies who were still on a ventilator after their first week of life were randomly assigned to receive either a 10-day course of hydrocortisone or a placebo. Random assignment — like a coin flip — is the fairest way to compare treatments, because it makes the two groups alike in every other way. In 2022, that study reported that hydrocortisone did not improve the babies' chances of surviving without serious lung disease, and made no difference to their development by age 2 [8]. But age 2 is very young, and a quick toddler check-up does not reliably predict how a child will manage the demands of a real classroom. So the researchers planned to bring the children back when they were older [9].

What the Researchers Did

This new study, called the HYBRiD Outcomes Study, invited the children from that original experiment to come back for a single, thorough visit between the ages of 5 and 7, at 19 hospitals across the United States, with visits taking place from 2017 through 2024 [1]. Out of the original 800 babies, 90 had died and 36 families chose not to continue, leaving 674 children eligible. The team gathered complete information on 545 of them — 272 who had received hydrocortisone and 273 who had received placebo.

What makes this study especially useful is what it measured. Instead of only testing IQ, the researchers looked at how each child was actually functioning in everyday life. Trained examiners — who did not know which children had received the steroid, so their judgment could not be swayed — checked four things: the child's thinking and learning, their movement and coordination, their early reading-and-number skills, and their physical stamina, measured by how far they could walk in six minutes. A child was counted as having a "functional impairment" if they had a difficulty in any one of these areas. This is close to the way schools decide whether a child needs extra support, so it reflects real life rather than just a test score [1].

What They Found

The two groups looked the same. About 71% of the children who had received hydrocortisone, and 73% of those who had received placebo, had a difficulty in at least one area — a difference so small it is essentially no difference at all. When the researchers looked at each area on its own — thinking, movement, learning, and stamina — the steroid and placebo groups again matched, with no meaningful gap in any of them. Average scores on the thinking test were nearly identical, and rates of cerebral palsy were similar in both groups. In short, the steroid neither helped nor hurt the children's development by school age.

The one difference the study found was that the children who had received hydrocortisone weighed a little less — about 0.9 kilograms, roughly two pounds — and were less likely to be in the heaviest weight range. Their height and head size were the same. Doctors are not sure what this small weight difference means, and it is a reason to keep an eye on growth rather than a cause for worry.

The most important number in the whole study was not about the steroid at all. Across both groups together, about 72% of these children — nearly three in four — had some functional difficulty by school age, most often with movement and coordination. These were all children who had been very sick as newborns, still needing a ventilator three to four weeks after birth. The study shows clearly that this group of children carries a high chance of needing extra developmental and educational support, no matter which treatment they received as babies [1].

What This Means for Families and Their Baby's Care

If your child received hydrocortisone on this schedule as a newborn, the reassuring news is that, years later, the steroid left no fingerprint — no extra problems with thinking, movement, learning, exercise, or cerebral palsy [7][9]. Given the worrying history with the older steroid dexamethasone, this kind of clean long-term safety result is genuinely valuable peace of mind [6]. The flip side is that this particular steroid plan did not protect the lungs or improve later development, so the study's authors say it should not be used for those purposes [1]. Doctors will still consider steroids in some situations, but this finding removes one hoped-for path to better long-term outcomes and pushes the conversation toward other options [10].

Perhaps the most practical message is about staying watchful. Because so many of these children turned out to have difficulties that only became clear once school demands arrived — difficulties a quick toddler check-up often misses — families and doctors should not be falsely reassured by a normal-seeming 2-year visit. A baby who needed the ventilator for weeks is a child worth following closely, with regular developmental check-ups and early access to physical therapy, learning help, and other support when needed [11]. The honest and empowering way to think about it is not that a treatment let the child down, but that a very premature start carries real risks the whole care team can watch for and act on early.

What Researchers Are Working On Next

This study settles one question: this hydrocortisone plan is not the answer for better long-term outcomes. So researchers are now asking whether other approaches — giving hydrocortisone earlier, or using a different steroid only in the babies at very highest risk — might do better, and they are committing to follow those children all the way to school age rather than stopping at age 2 [7][11]. Just as importantly, the high rate of difficulties found here is pushing the field to look beyond steroids altogether for new ways to protect both the lungs and the development of the most premature babies. Studies like this one, which honestly measure how children are really doing years later, give the next generation of treatments a clear and meaningful target to beat [12][2].

This article describes research about a sensitive subject — the long-term health of very premature children. It is meant for general information and is not medical advice. If you have questions about your own child's care, your neonatal or pediatric team can give guidance specific to your situation.

References

  1. DeMauro SB, Kirpalani H, Ziolkowski K, et al. Hydrocortisone in Preterm Infants and School-Age Functional Outcomes: Follow-Up of a Randomized Clinical Trial. JAMA Pediatr. 2025. doi:10.1001/jamapediatrics.2025.4801 ↩
  2. DeMauro SB. Neurodevelopmental outcomes of infants with bronchopulmonary dysplasia. Pediatr Pulmonol. 2021;56(11):3509–3517. doi:10.1002/ppul.25381 ↩
  3. Lapcharoensap W, Bennett MV, Xu X, Lee HC, Dukhovny D. Hospitalization costs associated with bronchopulmonary dysplasia in the first year of life. J Perinatol. 2020;40(1):130–137. doi:10.1038/s41372-019-0548-x ↩
  4. Bell EF, Hintz SR, Hansen NI, et al. Mortality, In-Hospital Morbidity, Care Practices, and 2-Year Outcomes for Extremely Preterm Infants in the US, 2013–2018. JAMA. 2022;327(3):248–263. doi:10.1001/jama.2021.23580 ↩
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  6. Doyle LW, Cheong JL, Hay S, Manley BJ, Halliday HL. Early (<7 days) systemic postnatal corticosteroids for prevention of bronchopulmonary dysplasia in preterm infants. Cochrane Database Syst Rev. 2021;10(10):CD001146. doi:10.1002/14651858.CD001146.pub6 ↩
  7. Shaffer ML, Baud O, Lacaze-Masmonteil T, Peltoniemi OM, Bonsante F, Watterberg KL. Effect of Prophylaxis for Early Adrenal Insufficiency Using Low-Dose Hydrocortisone in Very Preterm Infants: An Individual Patient Data Meta-Analysis. J Pediatr. 2019;207:136–142.e5. doi:10.1016/j.jpeds.2018.10.004 ↩
  8. Watterberg KL, Walsh MC, Li L, et al. Hydrocortisone to Improve Survival without Bronchopulmonary Dysplasia. N Engl J Med. 2022;386(12):1121–1131. doi:10.1056/NEJMoa2114897 ↩
  9. DeMauro SB, Kirpalani H, Ziolkowski K, et al. The HYdrocortisone for Bronchopulmonary Dysplasia Respiratory and Developmental (HYBRiD) outcomes study: protocol for a longitudinal cohort study. BMC Pediatr. 2024;24(1):737. doi:10.1186/s12887-024-05198-9 ↩
  10. Puia-Dumitrescu M, Wood TR, Comstock BA, et al. Dexamethasone, Prednisolone, and Methylprednisolone Use and 2-Year Neurodevelopmental Outcomes in Extremely Preterm Infants. JAMA Netw Open. 2022;5(3):e221947. doi:10.1001/jamanetworkopen.2022.1947 ↩
  11. Harmon HM, Jensen EA, Tan S, et al. Timing of postnatal steroids for bronchopulmonary dysplasia: association with pulmonary and neurodevelopmental outcomes. J Perinatol. 2020;40(4):616–627. doi:10.1038/s41372-020-0594-4 ↩
  12. Jensen EA, Dysart K, Gantz MG, et al. The Diagnosis of Bronchopulmonary Dysplasia in Very Preterm Infants: An Evidence-based Approach. Am J Respir Crit Care Med. 2019;200(6):751–759. doi:10.1164/rccm.201812-2348OC ↩