Two More Weeks of Gentle Breathing Support May Help a Premature Baby's Lungs Grow

What an Oregon trial and its two companion studies found when they kept stable preterm babies on nasal air pressure a little longer

Doctors have always removed a premature baby's gentle breathing support as soon as the baby looks stable, but nobody had ever tested whether that timing is right. A trial in Oregon kept babies on that support for two extra weeks and found that, six months later, their lungs were about a fifth larger and worked better. The extra support appeared safe and was well tolerated.

Why This Question Matters, and How Families Faced It Before

Babies born early often need help breathing. One of the gentlest forms of help is called continuous positive airway pressure, or CPAP: a soft set of prongs sits in the baby's nose and blows a steady, low-pressure stream of air that keeps the tiny air sacs in the lungs from collapsing between breaths. It is not a ventilator and it does not breathe for the baby; it simply keeps the lungs propped a little open so that each breath takes less effort. Three research papers from one trial in Oregon — a main report on lung growth [1], a study of chemicals in the babies' blood [2], and an analysis of dips in their oxygen levels [3] — have now put the timing of that decision to the test.

For decades, the moment a baby met a checklist of "stability" signs — breathing room air, no dips in oxygen, no tugging at the ribs — the prongs came off. Parents often experience this as a milestone, and it is: it usually means going home is closer. But the timing of that milestone was never based on research. When scientists reviewed what was known about how long babies should stay on CPAP, they found that almost every study had asked how to take babies off it, not when [4]. The few trials that existed compared different ways of weaning babies off, rather than testing whether staying on longer might help [5]. So each hospital wrote its own checklist, and the checklists were not identical.

Meanwhile, a second line of research was quietly making the question more interesting. A baby's lungs are not finished at birth. The little air sacs called alveoli — where oxygen crosses into the blood — keep multiplying through infancy and early childhood, and the path a child starts on tends to stay with them [6]. In one long study, children whose airways worked poorly in early infancy still had weaker lung function at age 22 [7]. Laboratory work suggested something surprising: gently stretching an immature lung makes it grow more tissue [8], and animals kept on sustained air pressure developed lungs with less twitchy airways [9] and, in one study of monkeys born early, more air sacs [10]. That raised a genuinely new idea: perhaps CPAP is not only a crutch for a struggling lung, but also a signal that tells a growing lung to build.

An earlier study by the same Oregon team had already hinted that extra CPAP changed lung volumes in stable premature babies [11]. And at the University of Alabama at Birmingham, a short 24-hour trial in that hospital's highest-level newborn intensive care unit found that babies who met the usual "ready to stop" checklist and were switched to a low-flow nasal tube had about four times as many oxygen dips over the next day — a middle value of 76 dips compared with 20 for babies kept on CPAP — along with more slow heartbeats [12]. That trial only lasted a day. The obvious next question was what happens over two weeks, and whether it leaves any lasting mark.

What the Researchers Did

The trial, called Extending CPAP Therapy in Stable Preterm Infants to Increase Lung Growth and Function (it has no short nickname), took place in the highest-level newborn intensive care unit at Oregon Health & Science University in Portland, Oregon, in the United States, between January 2020 and January 2023 [1]. It enrolled 100 babies born between 24 and 32 weeks of pregnancy who had needed CPAP and had just reached the standard checklist showing they were ready to come off.

At that point, a computer randomly assigned each baby to one of two paths. Fifty-four babies stayed on CPAP for another 14 days, breathing ordinary room air through the prongs at the same low pressure. Forty-six babies came off as usual. Twins were always assigned together, and the babies' nostrils were checked every three to four hours for redness.

Then the researchers did something unusual. About six months after the babies' due dates, families brought them back for a careful measurement of how big and how effective their lungs actually were. Using a brief, light sedative and a specialised research technique, the team measured the total volume of the air sacs and how well oxygen crossed from those sacs into the blood. Ninety-three of the 98 eligible babies came back for this test — a remarkably high 95%, with no family dropping out [1]. Two companion studies looked at the same babies from different angles: one analysed chemicals in their blood [2], and one counted dips in their oxygen levels [3].

What They Found

Babies who had stayed on CPAP for two extra weeks had, at six months, an air-sac volume of about 500 millilitres compared with about 418 millilitres in the babies who came off — a difference of roughly 82 millilitres, or about 20% more lung [1]. To picture it: that gap is a little more than the volume of a small espresso cup, added to lungs that are themselves only about the size of two clenched fists. Their lungs also moved oxygen into the blood about 21% more efficiently, and air flowed out of them about 14% faster on breathing tests. The difference had begun much earlier: by the end of the two weeks, while still in hospital, the extra-CPAP babies were already holding noticeably more air in their lungs at rest.

Two other findings will matter to parents. First, staying on CPAP was easy for the babies and coming off was not always easy. Only 2 of the babies asked to stay on had to stop early, whereas 10 of the 46 babies taken off — about one in five — had to be put back on CPAP because their breathing became laboured. Every breathing-related side effect the researchers judged possibly linked to the study happened in the group that came off early. In the group that stayed on, three babies had mild redness inside the nose, and none had skin breakdown or trouble feeding because of the prongs [1].

Second, and just as important: the extra CPAP did not improve any of the health outcomes families most care about. Rates of chronic lung disease were essentially identical (about 7% in each group), wheezing reported by parents during the first year was not significantly different (43% versus 57%), and the babies did not feed sooner or go home earlier [1]. This is a study about lung size and mechanics, not yet about a healthier childhood.

The blood study offers a possible explanation for what is going on. Sixty-four babies had a single blood sample analysed, and stopping CPAP changed the levels of about one in eight measurable chemicals within a few days — particularly fats waiting to be burned for energy. Over the fortnight, babies who stayed on CPAP gained 13% more weight while receiving exactly the same number of calories [2]. The researchers' idea is that breathing without CPAP simply takes more effort, and the energy spent on breathing is energy not spent on growing. They are careful to call this a hypothesis, not a proven mechanism. The third study reported fewer oxygen dips in the babies who stayed on CPAP; because its full text was not publicly available when this article was prepared, we describe it only as reported by others rather than quoting figures as confirmed [3].

What This Means for Families, and What Comes Next

If your baby is in a newborn intensive care unit today, nothing about this study changes what should happen to them, and it should not make you anxious about a decision already made. This was a single hospital, 100 babies, most of them born around 30 weeks, and it deliberately did not include the babies with the most severe lung problems. The measurement at the heart of the finding is a research tool that ordinary hospitals cannot perform. The result is real but modest, and the statistical range around it comes close to no difference at all.

What it does offer is a good question to ask, gently and without confrontation: how does this unit decide when CPAP comes off, and how often do babies here need to go back on it? That one-in-five return rate, echoed by the Alabama findings [12], suggests the standard checklists may identify babies who can manage without support rather than babies for whom stopping is genuinely best.

Researchers are now working on the questions this trial opened. How long should extra CPAP last, and at what pressure? Would it help the smallest and sickest babies, who were not studied here? Does bigger lung volume at six months translate into fewer chest infections, less asthma, and better breathing in adulthood — the trajectory that decades of follow-up studies suggest is set very early [6], [7]? Answering these needs larger trials across many hospitals, including families from more diverse backgrounds. Careful normal-range measurements in premature babies made this trial possible in the first place [13], just as the large CPAP trials of an earlier generation [14], [15] made CPAP itself the standard it is today. Progress in neonatal care usually looks like this: a small, careful study that turns a routine into a question.

References

  1. McEvoy CT, MacDonald KD, Go MA, et al. Extended Continuous Positive Airway Pressure in Preterm Infants Increases Lung Growth at 6 Months: A Randomized Controlled Trial. Am J Respir Crit Care Med. 2025;211(4):610–618. doi:10.1164/rccm.202411-2169OC ↩
  2. Ballard PL, MacDonald KD, Harris J, et al. Metabolic response to extended continuous positive airway pressure in premature infants. Pediatr Res. Published online December 22, 2025. doi:10.1038/s41390-025-04670-1 ↩
  3. Mamidi RR, Go MDA, Harris J, et al. Extended Continuous Positive Airway Pressure in Infants Born Preterm Decreases Intermittent Hypoxemia: A Secondary Analysis of a Randomized Controlled Trial. J Pediatr. Published online May 25, 2026:115165. doi:10.1016/j.jpeds.2026.115165 ↩
  4. Bamat N, Jensen EA, Kirpalani H. Duration of continuous positive airway pressure in premature infants. Semin Fetal Neonatal Med. 2016;21(3):189–195. doi:10.1016/j.siny.2016.02.005 ↩
  5. Todd DA, Wright A, Broom M, et al. Methods of weaning preterm babies <30 weeks gestation off CPAP: a multicentre randomised controlled trial. Arch Dis Child Fetal Neonatal Ed. 2012;97(4):F236–F240. doi:10.1136/adc.2011-300133 ↩
  6. Stocks J, Hislop A, Sonnappa S. Early lung development: lifelong effect on respiratory health and disease. Lancet Respir Med. 2013;1(9):728–742. doi:10.1016/S2213-2600(13)70118-870118-8) ↩
  7. Stern DA, Morgan WJ, Wright AL, Guerra S, Martinez FD. Poor airway function in early infancy and lung function by age 22 years: a non-selective longitudinal cohort study. Lancet. 2007;370(9589):758–764. doi:10.1016/S0140-6736(07)61379-861379-8) ↩
  8. Zhang S, Garbutt V, McBride JT. Strain-induced growth of the immature lung. J Appl Physiol. 1996;81(4):1471–1476. doi:10.1152/jappl.1996.81.4.1471 ↩
  9. Xue Z, Zhang L, Liu Y, Gunst SJ, Tepper RS. Chronic inflation of ferret lungs with CPAP reduces airway smooth muscle contractility in vivo and in vitro. J Appl Physiol. 2008;104(3):610–615. doi:10.1152/japplphysiol.00241.2007 ↩
  10. McEvoy CT, MacDonald KD, Shorey-Kendrick LE, et al. Nasal CPAP increases alveolar number in a rhesus monkey model of moderate prematurity. Eur Respir J. 2025;65(4):2400727. doi:10.1183/13993003.00727-2024 ↩
  11. Lam R, Schilling D, Scottoline B, et al. The effect of extended continuous positive airway pressure on changes in lung volumes in stable premature infants: a randomized controlled trial. J Pediatr. 2020;217:66–72.e1. doi:10.1016/j.jpeds.2019.07.074 ↩
  12. Yazdi SMZR, Carlo WA, Nakhmani A, Boateng EO, Aban I, Ambalavanan N, Travers CP. Extended CPAP or low-flow nasal cannula for intermittent hypoxaemia in preterm infants: a 24-hour randomised clinical trial. Arch Dis Child Fetal Neonatal Ed. 2024;109(5):557–561. doi:10.1136/archdischild-2023-326605 ↩
  13. Assaf SJ, Chang DV, Tiller CJ, et al. Lung parenchymal development in premature infants without bronchopulmonary dysplasia. Pediatr Pulmonol. 2015;50(12):1313–1319. doi:10.1002/ppul.23134 ↩
  14. Morley CJ, Davis PG, Doyle LW, Brion LP, Hascoet JM, Carlin JB; COIN Trial Investigators. Nasal CPAP or intubation at birth for very preterm infants. N Engl J Med. 2008;358(7):700–708. doi:10.1056/NEJMoa072788 ↩
  15. Subramaniam P, Ho JJ, Davis PG. Prophylactic or very early initiation of continuous positive airway pressure (CPAP) for preterm infants. Cochrane Database Syst Rev. 2021;10(10):CD001243. doi:10.1002/14651858.CD001243.pub4 ↩