Does Watching a Premature Baby's Brain Oxygen Help Them in the Long Run?

A large international study followed very premature babies to age two to test a brain-monitoring sensor — here is what families should know

Why researchers asked this question

When a baby is born extremely early — before 28 weeks of pregnancy, more than three months ahead of the due date — the first few days of life are the most fragile. Even with the best modern care, about one in five of these babies does not survive, and some of those who do grow up with lasting difficulties in movement, thinking, vision, or hearing [1], [2]. A major reason is that the brain of a very premature baby is delicate and still developing. In the first days, its blood vessels are fragile and its ability to keep a steady blood flow is immature, so the brain can be injured if its oxygen supply rises and falls too much [3], [4], [5].

Doctors have long wanted a way to catch those dangerous dips in brain oxygen before harm is done. One promising tool is called cerebral oximetry. It is a soft sensor placed on the baby's forehead that shines harmless near-infrared light through the skin to estimate how much oxygen the brain is getting, and it shows that number continuously on a monitor. An earlier study had shown the sensor could reduce the amount of time a baby's brain spent low on oxygen during the first three days [6]. The natural next question was the one that matters most to families: does using this monitor actually help babies do better as they grow? Researchers know a great deal about the risks these babies face [7], [8], which is exactly why they wanted to test whether the monitor could change them.

How the study was done

To answer this, scientists ran one of the largest trials ever done in newborn care, called SafeBoosC-III. They enrolled 1,601 extremely premature babies at 70 hospitals across 17 countries [1], [2]. Within six hours of birth, each baby was randomly assigned — by chance, like a coin flip — to one of two groups. In one group, doctors used the forehead brain-oxygen sensor for the first 72 hours and followed a guide telling them what to do if the oxygen level dropped too low. In the other group, babies received the same excellent care doctors normally give, just without the sensor [1]. Comparing two groups chosen by chance is the fairest way to tell whether a treatment truly makes a difference, because the groups end up very similar in every other way.

At first, when the babies reached the age they would have been at 36 weeks of pregnancy, the two groups had done about equally well — the monitor had not lowered the rate of death or serious brain injury [2]. But a brain scan in the first weeks does not always predict how a child will actually develop [3]. So the researchers did something very important: they followed the children to about two years of age to see how they were really doing. This new study, led by Dr. Marie Isabel Skov Rasmussen and colleagues, is the long-term answer [1].

What they found

The team was able to check on 1,438 of the children — 90% of everyone in the original study, which is an excellent follow-up rate for a trial this size [1]. They looked at two main things: whether each child had either died or developed a moderate or severe disability (in movement, thinking, vision, or hearing), and how the children scored on a standard test of early thinking and learning skills called the Bayley test [1].

To make sure they did not miss children who were hard to reach, the researchers gathered information in three ways: from formal medical follow-up visits, from questionnaires filled out by parents, and, when neither was available, from a careful review of the child's existing medical records [1]. This practical approach is part of why they managed to find out how 9 in 10 of the children were doing — an unusually complete result for a study that follows babies for two years, since families move, change hospitals, or simply lose touch over time.

The results were strikingly similar between the two groups. Death or moderate-to-severe disability had occurred in about 47 out of every 100 children who had the brain-oxygen monitor, and about 48 out of every 100 who did not — essentially the same [1]. The average thinking-and-learning scores were also nearly identical: 92.8 in the monitored group and 93.2 in the other [1]. When researchers looked separately at cerebral palsy (a movement disorder), hearing, and thinking skills, the two groups again matched closely [1]. There was one difference — slightly less vision impairment in the monitored group — but the researchers believe this was most likely down to chance, the kind of small difference that appears when you measure many things at once [1]. Encouragingly, when parents were asked, almost all of them — about 97 in every 100 in both groups — described their child as thriving [1].

What this means for families

The honest takeaway is that, in this large and careful study, using the brain-oxygen sensor routinely in the first three days did not make the babies healthier or help their development by age two compared with usual newborn intensive care [1], [2]. That may sound disappointing, but it is genuinely valuable knowledge. It means families and doctors do not need to worry that a baby missed out by not having this particular monitor, and it helps hospitals focus their resources on the things that do make a difference.

It is also worth understanding what the study does and does not say. Because not quite enough children could be tested to settle every question, the researchers could not completely rule out a small benefit or a small downside for the combined measure of death-or-disability [1]. For the thinking-and-learning scores, though, the answer was clearer: there was no meaningful average difference, and a brain-scan study of the same children supported that conclusion [1]. Importantly, the study tested one specific way of using the monitor — only for three days, without a strict rule about exactly what to do when the oxygen dipped, and at a time when not all staff had completed the optional training [1]. So this is not proof that a baby's brain oxygen does not matter; it shows that this particular approach, used this way, did not change the outcomes that families care about [3], [5].

The wider picture for families of extremely premature babies remains one of cautious hope. Survival and healthy development have improved over the decades, even though the risks at this early stage are real and well studied [9], [10], [11]. Good newborn care is made up of many small, proven steps working together, and researchers continue to test each new idea carefully — as they have done for years with treatments like caffeine for breathing in premature babies — precisely so that families can trust what is offered [12].

What researchers are working on next

Scientists are not giving up on the idea behind the monitor; they are trying to use it more wisely. Future studies may focus on the specific situations where a baby's brain oxygen is most likely to be threatened — such as low blood pressure, low blood counts, or certain heart-related problems common in premature babies — and may pair the monitor with a clear, agreed plan of action, use it for longer than three days, and make sure every team member is fully trained [1]. Researchers also plan to follow children to school age, when tests of thinking and learning are more accurate, to be even more certain about the long-term picture [1]. It also helps to remember what a result like this really represents. A study that finds "no difference" can feel anticlimactic, but it is exactly how medicine protects babies from treatments that add cost, alarms, or false reassurance without delivering real benefit. The researchers were careful to point out that their study could not rule out a small effect, and that they had tested only one particular way of using the monitor, for a short window of time. That honesty is a strength, not a weakness — it tells doctors precisely what still needs to be studied rather than overselling a tidy answer.

For now, the most important message for families is a reassuring one: a baby's care does not depend on this single device, and the choice to use it or not did not change how these children were doing two years later. Parents who see this sensor on another baby in the unit, or who are offered it for their own child, can take comfort that it is painless and safe, and that the dedicated team around their baby — not any one machine — is what carries them through.

References

  1. Rasmussen MIS, Hansen ML, Pellicer A, et al. Cerebral Oximetry in Extremely Preterm Infants: 2-Year Follow-Up of the SafeBoosC-III Randomized Clinical Trial. JAMA Pediatrics. 2026;180(6):619–627. doi:10.1001/jamapediatrics.2026.1066 ↩
  2. Hansen ML, Pellicer A, Hyttel-Sørensen S, et al. Cerebral Oximetry Monitoring in Extremely Preterm Infants. New England Journal of Medicine. 2023;388(16):1501–1511. doi:10.1056/NEJMoa2207554 ↩
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  9. Marlow N, Wolke D, Bracewell MA, Samara M. Neurologic and developmental disability at six years of age after extremely preterm birth. New England Journal of Medicine. 2005;352(1):9–19. doi:10.1056/NEJMoa041367 ↩
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