Helping a Tiny Baby Breathe Before the Cord Is Cut

What a large North American study, and the follow-up analysis published a year later, learned about the first two minutes of an extremely premature life

A large study in the United States and Canada tested whether helping very premature babies breathe before the umbilical cord is cut protects them from bleeding in the brain. It did not. But a second analysis of the same 570 babies found those babies settled faster in the first minute and needed a breathing tube less often — while also getting colder. Here is what that means for families.

Why This Question Matters

A baby born at 23 to 28 weeks of pregnancy weighs roughly as much as a large mango. Everything about the first two minutes after birth is fragile, and one of the most fragile things is the brain. The blood vessels in a premature baby's brain are delicate, and bleeding into the fluid-filled spaces at the centre of the brain — doctors call this intraventricular haemorrhage — is common. Most of these bleeds are small and cause no lasting problem, but the larger ones can affect a child's later development, so preventing them has been a central goal of newborn medicine for decades. That is exactly what the study described here set out to do [1], and what a follow-up analysis of the same babies re-examined from a different angle a year later [2].

How Families and Doctors Used to Face This

For most of the twentieth century, the umbilical cord was clamped and cut within seconds of birth so the baby could be handed to a waiting team. That seemed obviously right: get the baby to the resuscitation table, get help started. Over the past fifteen years that assumption was overturned. When researchers combined the results of many trials, they found that simply waiting — leaving the cord uncut for at least half a minute — reduced the chance of a premature baby dying before going home [3]. Waiting became standard practice worldwide.

The reason waiting helps is thought to be something called placental transfusion. While the cord is still attached, blood continues to flow from the placenta into the baby, giving the baby extra blood volume and extra red blood cells for the difficult days ahead [4]. But this created a painful dilemma for delivery-room teams. The babies who would benefit most from waiting are the tiniest and sickest — and those are exactly the babies who are not breathing and appear to need urgent help. Standing beside a limp, silent baby for a full minute, doing nothing but waiting, is one of the hardest things a neonatal team is asked to do.

Laboratory research in newborn lambs suggested a solution. If the lungs were opened up with gentle breathing support before the cord was cut, the sudden drop in heart rate and blood flow that normally follows cutting the cord did not happen [5], and oxygen delivery to the body and brain was better [6]. The idea was elegant: instead of choosing between waiting and helping, do both at once. Nobody had tested it properly in human babies.

What the Researchers Did

The study, called VentFirst — its full registered title is VentFirst: A Multicenter RCT of Assisted Ventilation During Delayed Cord Clamping for Extremely Preterm Infants — was run at 12 hospitals across the United States and Canada between September 2016 and February 2023. Mothers expected to deliver between 23 and 28 weeks of pregnancy agreed in advance to take part, and were assigned by chance to one of two approaches at the moment of birth.

In the first approach, a neonatal doctor came to the mother's side and, 30 seconds after birth, began breathing support while the cord was still attached — gentle continuous pressure through a small face mask if the baby was breathing, or assisted breaths if the baby was not. The cord was cut at about two minutes. In the second, standard approach, the cord was cut at 30 seconds if the baby was not breathing and at up to 60 seconds if the baby was, and breathing support began at the warming table as usual. Five hundred seventy babies took part.

The main question was whether the first approach reduced brain bleeding, checked by an ultrasound scan of the head at seven to ten days and graded using a scale in use since 1978 [7], or death in the first week.

What Was Found

It made no difference. About 35 babies in every 100 in the breathing-support group and about 33 in every 100 in the standard group had a brain bleed or died in the first week — a difference so small it is best read as no difference at all. This was true for babies who were breathing on their own and for those who were not. It was also true across the whole range of gestational ages studied. The researchers had planned to enrol 940 babies and stopped at 570 when it became clear the answer was unlikely to change.

Then, a year later, the same team looked again — this time not at the ultrasound a week later, but at the first minutes of life themselves [2]. Here the picture was different. Among babies who were not breathing well, those who received breathing help with the cord attached needed a breathing tube less often: about 47 in every 100, compared with 62 in every 100. Almost all of that benefit was in the slightly more mature babies, those born at 26 to 28 weeks, where the numbers were 23 in every 100 versus 48. Their heart rates recovered faster — 42 in every 100 had a healthy heart rate at one minute, compared with 24 in every 100 — and their one-minute condition scores were better. Babies who had been getting extra blood while receiving help also had slightly richer blood a day later.

There was a cost. More of these babies got cold: 35 in every 100 had a temperature below 36.5 °C, compared with 21 in every 100. Interestingly, this had nothing to do with how long the cord stayed attached. It was linked to how small the baby was and to being born by caesarean section — in other words, to being uncovered in a cool operating theatre, not to the waiting itself. Among babies who were breathing well, the only difference found was that fewer became too warm.

What This Means for Families

If your baby is born very early, the team will almost certainly wait before cutting the cord. That practice is well established, is supported by strong evidence, and is not in question here [8]. What this study tested was an additional step — starting breathing support during that wait — and it did not show a reduction in brain bleeding. So this is not something to ask for, and its absence is not something to worry about.

What the studies do show is that the approach is safe and workable. Earlier small trials had already suggested it could be done [9], and human measurements had shown that a baby's own breathing helps blood move from the placenta [10] — which is why teams often gently stimulate a premature baby to take breaths during the wait. That gentle rubbing you may see is not impatience; it is treatment. If your baby did need a breathing tube in the delivery room, that too is a normal and appropriate step, not a sign that anything went wrong: more than half of the very premature babies in this study who were not breathing well received one, in both groups.

It is also worth knowing that a second large trial, run across nine hospitals in the Netherlands and known as ABC3 — short for Aeration, Breathing, Clamping — tested a closely related idea in 669 babies and also found no benefit for its main outcome [11]. When two large, careful studies point the same way, the field takes that seriously.

What Researchers Are Working On Next

Three things follow from all this. Researchers now argue that future trials should measure what happens in the first minutes — heart rate, breathing, whether a tube is needed — rather than a brain scan a week later, because that is where the effects are actually visible [12]. Engineers and clinicians are working on warmed platforms and operating-theatre setups so that any baby cared for beside their mother stays warm. And attention is shifting toward babies born at 26 to 28 weeks who are struggling to breathe, since that is the group where the signal was strongest.

For now, the honest position is one that good medicine reaches often: a beautiful idea, carefully tested, did not deliver what was hoped [13]. The waiting still helps. Whether helping the baby breathe during that wait adds anything remains an open question — and 570 families made answering it possible.

References

  1. Fairchild KD, Petroni GR, Varhegyi NE, et al. Ventilatory assistance before umbilical cord clamping in extremely preterm infants: a randomized clinical trial. JAMA Netw Open. 2024;7(5):e2411140. doi:10.1001/jamanetworkopen.2024.11140 ↩
  2. Fang JL, Fairchild KD, Petroni GR, et al. Physiologic transition during delayed cord clamping with assisted ventilation in preterm infants: a secondary analysis of the VentFirst trial. JAMA Netw Open. 2025;8(11):e2545258. doi:10.1001/jamanetworkopen.2025.45258 ↩
  3. Seidler AL, Aberoumand M, Hunter KE, et al. Deferred cord clamping, cord milking, and immediate cord clamping at preterm birth: a systematic review and individual participant data meta-analysis. Lancet. 2023;402(10418):2209-2222. doi:10.1016/S0140-6736(23)02468-602468-6) ↩
  4. Katheria AC, Lakshminrusimha S, Rabe H, McAdams R, Mercer JS. Placental transfusion: a review. J Perinatol. 2017;37(2):105-111. doi:10.1038/jp.2016.151 ↩
  5. Bhatt S, Alison BJ, Wallace EM, et al. Delaying cord clamping until ventilation onset improves cardiovascular function at birth in preterm lambs. J Physiol. 2013;591(8):2113-2126. doi:10.1113/jphysiol.2012.250084 ↩
  6. Polglase GR, Dawson JA, Kluckow M, et al. Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping) improves systemic and cerebral oxygenation in preterm lambs. PLoS One. 2015;10(2):e0117504. doi:10.1371/journal.pone.0117504 ↩
  7. Papile LA, Burstein J, Burstein R, Koffler H. Incidence and evolution of subependymal and intraventricular hemorrhage: a study of infants with birth weights less than 1,500 gm. J Pediatr. 1978;92(4):529-534. doi:10.1016/S0022-3476(78)80282-080282-0) ↩
  8. Seidler AL, Libesman S, Hunter KE, et al. Short, medium, and long deferral of umbilical cord clamping compared with umbilical cord milking and immediate clamping at preterm birth: a systematic review and network meta-analysis with individual participant data. Lancet. 2023;402(10418):2223-2234. doi:10.1016/S0140-6736(23)02469-802469-8) ↩
  9. Katheria A, Poeltler D, Durham J, et al. Neonatal resuscitation with an intact cord: a randomized clinical trial. J Pediatr. 2016;178:75-80. doi:10.1016/j.jpeds.2016.07.053 ↩
  10. Brouwer E, Knol R, Kroushev A, et al. Effect of breathing on venous return during delayed cord clamping: an observational study. Arch Dis Child Fetal Neonatal Ed. 2022;107(1):65-69. doi:10.1136/archdischild-2020-321431 ↩
  11. Knol R, Brouwer E, van den Akker T, et al. Physiological versus time based cord clamping in very preterm infants (ABC3): a parallel-group, multicentre, randomised, controlled superiority trial. Lancet Reg Health Eur. 2025;48:101146. doi:10.1016/j.lanepe.2024.101146 ↩
  12. Barlow K, Newman-Lindsay S, Giusto E, Katheria A, Lakshminrusimha S. Does ventilatory assistance before umbilical cord clamping reduce the risk of early death or intraventricular hemorrhage in extremely preterm infants? J Perinatol. 2025;45(6):881-884. doi:10.1038/s41372-025-02258-5 ↩
  13. Lakshminrusimha S, Saugstad OD, Vento M. Lung aeration during deferred cord clamping—no additional benefits in infants born preterm? J Pediatr. 2023;255:11-15.e6. doi:10.1016/j.jpeds.2022.11.029 ↩