Steroids for Premature Babies' Lungs: What Parents and Families Should Know

A plain-language guide to why these medicines are used, what they can do, and why doctors are so careful with them

Why a tiny baby might need a steroid

Babies born very early — many weeks before their due date — often have lungs that are not finished growing. To survive, the smallest of these babies may need a breathing machine, called a ventilator, that pushes air into their lungs through a tube. The machine is lifesaving, but over days and weeks it can also irritate and inflame the delicate, unfinished lung tissue. That ongoing inflammation is part of how a chronic lung condition of prematurity, called bronchopulmonary dysplasia, or BPD, develops. BPD means the lungs stay stiff and inflamed and the baby keeps needing extra oxygen and breathing support far longer than hoped.

Corticosteroids — usually shortened to "steroids" — are powerful anti-inflammation medicines. (These are not the muscle-building steroids that sometimes make the news; they are the same family of drugs used to calm asthma flares or severe allergies.) In a premature baby, a steroid can quiet the lung inflammation enough that the baby can finally come off the ventilator. That is the central hope behind using them. The catch, and the reason this is one of the most carefully weighed decisions in newborn intensive care, is that these medicines can also carry real risks — especially for the developing brain.

The hard lesson from the past

In the 1980s and 1990s, doctors gave premature babies a steroid called dexamethasone early and in high doses, hoping to prevent BPD. It did reduce lung disease. But as those children grew, studies found that the babies who had received those high, early doses had more cerebral palsy — a disorder of movement and muscle control caused by injury to the developing brain. Today's careful summaries of all the early-steroid trials still find that the lung benefit comes paired with a higher risk of cerebral palsy and developmental problems when steroids are given in the first week of life ^[1].

That history changed everything. The leading pediatric professional body now advises doctors to avoid routine and high-dose steroid use, to reserve these drugs for babies at genuinely high risk of serious lung disease, to involve parents in the decision, and to remember that the dose, the total amount, and the timing all matter — with the old high-dose dexamethasone schedules being the most clearly harmful ^[2]. In short: steroids are not given lightly, and not to every premature baby.

The most common course today: low-dose dexamethasone (the "DART" schedule)

For a baby who is still stuck on the ventilator after the first week or two with developing or established BPD, the most widely used steroid course comes from a study called DART ^[3]. It uses a much lower total dose of dexamethasone than the old harmful regimens, given over ten days and tapered down step by step.

What this course mainly does is help babies come off the breathing machine. In the DART study, 60% of babies given the steroid were successfully off the ventilator by day 10, compared with only 12% of babies who got a dummy treatment ^[3]. At this low dose, the babies did not show the obvious side effects — high blood sugar, high blood pressure — and there were no bowel injuries. A follow-up two years later did not find clear evidence of long-term harm, but the study was small, so it could not fully prove the course is safe for the brain ^[4]. This is why doctors describe it honestly: it is a medicine that helps the lungs come off the ventilator, not one proven to be free of long-term effects.

A gentler steroid: hydrocortisone

Because of the worries about dexamethasone and the brain, researchers also tested a milder steroid called hydrocortisone, which is thought to be gentler on brain development.

One study, called SToP-BPD, gave hydrocortisone to babies still on the ventilator at one to two weeks of age ^[5]. It did not reduce the combined measure of "death or BPD," but fewer babies died, and the babies came off the ventilator more easily. A two-year follow-up found no difference in development between the groups, and the survival benefit held up ^[6]. A larger American study run by the NICHD research network tested hydrocortisone a bit later, between two and four weeks of age ^[7]. It also helped babies get off the ventilator and — reassuringly — did not worsen development at age two, though it did not clearly reduce BPD itself and led to a little more treated high blood pressure. As an expert commentary accompanying that study put it, hydrocortisone is helpful but not a cure-all ^[8].

A different problem: low blood pressure and "adrenal insufficiency"

Steroids in premature babies are not only about lungs. The body normally makes its own natural steroid, called cortisol, to handle stress. The most premature babies sometimes cannot make enough of it — a situation doctors call relative adrenal insufficiency. One sign is dangerously low blood pressure that does not respond to the usual treatments. The early shortage of this natural steroid may also allow the inflammation that leads to BPD.

Two approaches grew out of this idea. The first is giving a low dose of hydrocortisone preventively, very early, to the most premature babies. An early study called PROPHET tried this but had to stop early because some babies developed holes in the bowel — and importantly, those bowel injuries clustered in babies who were also receiving a common pain-and-heart medicine called indomethacin ^[9]. A later, better-designed study called PREMILOC refined the approach: it gave a low hydrocortisone dose in the first day of life but deliberately held back those other medicines for the first 24 hours ^[10]. This time, more babies survived without BPD, the bowel injuries did not increase, and development at two years was not harmed ^[11]. When researchers pooled all the similar studies together, they confirmed the same pattern: early low-dose hydrocortisone helped babies survive without BPD, but combining it with that other medicine raised the risk of bowel injury ^[12]. The clearest safety lesson: these two medicines should not be given together in the first days of life.

The second approach treats the low blood pressure directly. When a baby's blood pressure stays dangerously low despite the usual support, a "stress dose" of hydrocortisone can help stabilize it and reduce the need for blood-pressure-supporting drugs ^[13]. Here the steroid is simply replacing the cortisol the baby cannot make.

Comparing the approaches at a glance

The risks, in plain terms

The most serious historical concern is brain development — cerebral palsy and learning or movement problems — and this risk is tied mainly to high doses of dexamethasone given very early. The lower-dose, later courses used today appear far safer for the brain, but the studies are not large enough to promise zero risk, which is why doctors are honest about the uncertainty. Other, usually more manageable effects include higher blood sugar and higher blood pressure during treatment; these are watched for closely and usually settle once the course is finished or the dose is lowered. The bowel-injury risk is real but is largely tied to combining early hydrocortisone with specific other medicines, which careful timing avoids.

What is still uncertain

Even after decades of research, doctors still cannot say exactly which steroid, at which dose, started on which day, is best ^[14]. The careful summaries agree that steroids given after the first week genuinely help selected high-risk babies, but they cannot identify a single best schedule, which is why the low-dose DART course continues largely by agreement among experts rather than by proof it beats every alternative ^[15].

For families, the practical takeaways are these. Steroids are reserved for babies at real risk of serious lung disease, not given routinely. The lowest effective dose is used deliberately, because the harms of the past came from high doses. Different steroids and timings serve different problems — lung inflammation, very early prevention in the smallest babies, or dangerously low blood pressure. And the decision is meant to be shared: a good neonatal team will explain why a steroid is being considered for your baby specifically, what it is expected to achieve, and what remains unknown. Asking those questions is not second-guessing the team — it is exactly the kind of careful, informed conversation that the medicine's difficult history calls for, and a good team will welcome it.

References

1. 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 ↩
2. Cummings JJ, Pramanik AK; Committee on Fetus and Newborn. Postnatal corticosteroids to prevent or treat chronic lung disease following preterm birth. Pediatrics. 2022;149(6):e2022057530. doi:10.1542/peds.2022-057530 ↩
3. Doyle LW, Davis PG, Morley CJ, McPhee A, Carlin JB; DART Study Investigators. Low-dose dexamethasone facilitates extubation among chronically ventilator-dependent infants: a multicenter, international, randomized, controlled trial. Pediatrics. 2006;117(1):75–83. doi:10.1542/peds.2004-2843 ↩
4. Doyle LW, Davis PG, Morley CJ, McPhee A, Carlin JB; DART Study Investigators. Outcome at 2 years of age of infants from the DART study: a multicenter, international, randomized, controlled trial of low-dose dexamethasone. Pediatrics. 2007;119(4):716–721. doi:10.1542/peds.2006-2806 ↩
5. Onland W, Cools F, Kroon A, Rademaker K, Merkus MP, Dijk PH, et al; STOP-BPD Study Group. Effect of hydrocortisone therapy initiated 7 to 14 days after birth on mortality or bronchopulmonary dysplasia among very preterm infants receiving mechanical ventilation: a randomized clinical trial. JAMA. 2019;321(4):354–363. doi:10.1001/jama.2018.21443 ↩
6. Halbmeijer NM, Onland W, Cools F, Swarte R, van der Heide-Jalving M, Merkus MP, van Kaam AH. Effect of systemic hydrocortisone initiated 7 to 14 days after birth in ventilated preterm infants on mortality and neurodevelopment at 2 years' corrected age: follow-up of a randomized clinical trial. JAMA. 2021;326(4):355–357. doi:10.1001/jama.2021.9380 ↩
7. Watterberg KL, Walsh MC, Li L, Chawla S, D'Angio CT, Goldberg RN, et al; Eunice Kennedy Shriver NICHD Neonatal Research Network. Hydrocortisone to improve survival without bronchopulmonary dysplasia. N Engl J Med. 2022;386(12):1121–1131. doi:10.1056/NEJMoa2114897 ↩
8. Greenough A. Hydrocortisone to prevent bronchopulmonary dysplasia — not a silver bullet. N Engl J Med. 2022;386(12):1181–1183. doi:10.1056/NEJMe2200247 ↩
9. Watterberg KL, Gerdes JS, Cole CH, Aucott SW, Thilo EH, Mammel MC, et al. Prophylaxis of early adrenal insufficiency to prevent bronchopulmonary dysplasia: a multicenter trial. Pediatrics. 2004;114(6):1649–1657. doi:10.1542/peds.2004-1159 ↩
10. Baud O, Maury L, Lebail F, Ramful D, El Moussawi F, Nicaise C, et al; PREMILOC trial study group. Effect of early low-dose hydrocortisone on survival without bronchopulmonary dysplasia in extremely preterm infants (PREMILOC): a double-blind, placebo-controlled, multicentre, randomised trial. Lancet. 2016;387(10030):1827–1836. doi:10.1016/S0140-6736(16)00202-600202-6) ↩
11. Baud O, Trousson C, Biran V, Leroy E, Mohamed D, Alberti C; PREMILOC Trial Group. Association between early low-dose hydrocortisone therapy in extremely preterm neonates and neurodevelopmental outcomes at 2 years of age. JAMA. 2017;317(13):1329–1337. doi:10.1001/jama.2017.2692 ↩
12. 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 ↩
13. Ng PC, Lee CH, Bnur FL, Chan IH, Lee AW, Wong E, et al. A double-blind, randomized, controlled study of a "stress dose" of hydrocortisone for rescue treatment of refractory hypotension in preterm infants. Pediatrics. 2006;117(2):367–375. doi:10.1542/peds.2005-0869 ↩
14. Doyle LW, Cheong JL, Hay S, Manley BJ, Halliday HL. Late (≥7 days) systemic postnatal corticosteroids for prevention of bronchopulmonary dysplasia in preterm infants. Cochrane Database Syst Rev. 2021;11(11):CD001145. doi:10.1002/14651858.CD001145.pub5 ↩
15. Onland W, De Jaegere AP, Offringa M, van Kaam A. Systemic corticosteroid regimens for prevention of bronchopulmonary dysplasia in preterm infants. Cochrane Database Syst Rev. 2017;1(1):CD010941. doi:10.1002/14651858.CD010941.pub2 ↩