Can a Baby's Own Cord Blood Protect the Lungs? What Five Years of Follow-Up Can and Cannot Tell Families

A 2026 report from a hospital in China on very preterm babies given their own cord blood cells

Researchers in Guangzhou, China, tested whether giving very premature babies a single infusion of their own cord blood cells in the first day of life could help prevent a serious lung condition called bronchopulmonary dysplasia, or BPD. Five years later, the children who received the cells scored better on two parts of a parent-completed developmental questionnaire (fine motor skills and personal-social skills) and had fewer reports of night-time cough [1]. The study was small and the babies were not assigned by chance, so these results are encouraging but not proof, and the researchers say larger trials are needed.

Why babies born very early often have long-lasting lung trouble

When a baby is born many weeks early, the lungs are not finished growing. Most very premature babies need help with breathing through machines and extra oxygen. For some, that help, along with the normal stress of being born too soon, leaves the lungs scarred and underdeveloped. Doctors call this bronchopulmonary dysplasia, and it is the most common long-term complication of very preterm birth [2]. Families often come to know it as "chronic lung disease" or "needing oxygen at home."

BPD matters beyond breathing. A large French study that followed children born very early found that those who had BPD were more likely to have developmental difficulties and to need more healthcare at ages five to six than those who did not [3]. That is one reason researchers work so hard to prevent it, and why doctors look for treatments that protect both the lungs and the developing brain [4].

How doctors have tried to prevent it, and why stem cells became interesting

Over the years, neonatal teams have tried many approaches, including gentler breathing support, careful nutrition, and medicines such as steroids. Steroids are a good example of how difficult this work is. One large European trial found that a low dose of a steroid called hydrocortisone, given very early, helped more extremely premature babies survive without BPD [5]. A larger American trial later did not find a clear improvement on that same measure [6]. We describe the steroid story in more detail in a companion article (https://inneosight.org/en-US/articles/postnatal-corticosteroids-bpd).

Because none of these approaches is a complete answer, researchers have turned to stem cells, which are cells that can help tissues repair themselves and calm harmful inflammation. A careful review of the research up to 2017 concluded that there was not yet enough evidence to say whether one kind of stem cell, called mesenchymal stem cells, helps or harms premature babies [7]. Scientists also listed the questions that still need answers: which cells, how many, when, for which babies, and how to give them [8]. A Korean team tested donor-derived cells placed into the windpipe of very premature babies [9]; by the time the children were five, that team had not found a clear difference in breathing or development between the groups, as the Guangzhou researchers describe [10].

The Guangzhou team took a different approach. After a baby is born, the blood left in the umbilical cord and placenta can be collected. It contains a mixture of young blood cells. The team collected each baby's own cord blood, separated out a group of cells called mononuclear cells, and gave them back to the same baby through a vein within the first day of life. An early report found that this looked safe and was linked with less time on breathing support [11], and the team then ran a larger study with a placebo group and followed the children for two years [12]. The new paper is the five-year check-in on those same children [1].

What the researchers did

The study took place at one hospital, Guangdong Women and Children Hospital in China, and enrolled 62 babies born before 32 weeks of pregnancy between mid-2018 and the start of 2020 [1]. Twenty-nine babies received their own cord blood cells and 33 received an infusion of salt water as a placebo, all within 24 hours of birth. The parents, the doctors, and the research team were kept unaware of which baby received which, so that hopes and expectations would not colour what they noticed.

One important detail is that the babies were not randomly assigned, which means the two groups were not formed by a coin toss. This is a "nonrandomised" study, and it is weaker evidence than a randomised trial, because the groups may differ in ways that affect the results [1].

When the children were five, researchers reached 23 of the treated children and 30 of the comparison children by telephone. Seven children could not be reached, mostly because families had changed phone numbers [1]. Parents completed a well-known questionnaire called the Ages and Stages Questionnaire, which asks about everyday skills such as using a pencil, playing with other children, and solving simple problems. Twenty-two parents of treated children and 26 of comparison children completed it. Each skill area is scored from 0 to 60, with higher scores meaning stronger skills.

What the researchers found

In fine motor skills, the use of the hands and fingers, treated children scored an average of about 53 compared with about 45 in the comparison group. In personal-social skills, such as playing and interacting with others, the scores were about 57 versus about 50 [1]. In other areas, including overall score, gross motor skills such as running and climbing, communication, and problem solving, the differences were small enough that chance could explain them [1]. Serious problems such as cerebral palsy were rare and similar in both groups: one treated child and two comparison children.

On lung health, no child in either group had been hospitalised for pneumonia in the past year, and no child needed extra oxygen [1]. Seven of the 23 treated children were reported to have a night-time cough, compared with 11 of 30 comparison children. (The published paper prints the comparison figure as 70 percent, which does not match 11 out of 30, so we rely on the counts.) Wheezing was actually reported a little more often in treated children, 5 of 23 compared with 3 of 30, although this difference could easily be due to chance. Height and weight were similar in both groups [1]. The authors described the safety information as reassuring.

What this means, and what it does not mean

It is natural to hope that these results mean a new treatment is coming. The honest answer is that they are a promising hint. Several things keep us from going further. The study was small, with only about 50 children in the follow-up. The babies were not randomly assigned, and the treated group had fewer boys and differences in parents' education and smoking, which can themselves influence how children develop [1]. The developmental scores came from questionnaires that parents filled out rather than from a specialist testing the child. Only five babies in the study were born before 28 weeks, so we do not know whether the approach would work for the tiniest babies, who are the most likely to develop BPD [1].

The scientists who wrote the paper share these cautions. They concluded that the treatment showed high potential but that further randomised, placebo-controlled trials are essential to confirm it [1]. Importantly, the main finding was not better lung outcomes, which is the original goal of the treatment, but differences in two developmental areas. That is something researchers will want to understand better before anyone draws conclusions.

What this means for families today

If your baby is in the NICU, this study does not change what your care team will offer. Stem cell infusions for BPD prevention are not a standard treatment, and families should be wary of clinics outside research studies that offer cell treatments. The proven steps that protect your baby's lungs remain the focus of care, as summarised in recent reviews [4].

If you hear about a stem cell research study, you can ask the team some simple questions. What is being tested, and why? Is it a randomised study? What has been shown about safety so far? How long will my child be followed? Taking part is always voluntary, and saying no will not affect your baby's regular care. If your child has had BPD, regular developmental check-ups are worthwhile whether or not any new treatment is used, because early support for movement, language, and learning makes a real difference [3].

What researchers are working on next

The next step is a larger study in which babies are randomly assigned to receive either their own cord blood cells or a placebo, at several hospitals, with special attention to the smallest and youngest babies. Researchers will also want to check children's development with hands-on testing at school age instead of relying only on questionnaires, and to work out which cells in the cord blood matter most, how much should be given, and when [8]. A related story about stem cell research in newborns with brain injury from low oxygen is told in another In[Neo]Sight article (https://inneosight.org/en-US/articles/temcell-hie2025).

A hopeful signal that needs a bigger test

Five years after a single infusion, the children in this small study appear to be doing well, with no sign of late harm and with some encouraging results in fine motor and social skills [1]. That is worth following up, and the next, larger trials should tell us whether it is a real benefit or a coincidence. For now, families can take comfort in knowing that researchers are working hard on this problem, and that careful trials are how real progress is made.

References

  1. Ren Z, Han J, Zhang Q, et al. Five-year follow-up of phase II trial of autologous cord blood mononuclear cells for bronchopulmonary dysplasia prevention in very preterm infants. Stem Cells Transl Med. 2026;15(8):szag045. doi:10.1093/stcltm/szag045 ↩
  2. Gilfillan M, Bhandari A, Bhandari V. Diagnosis and management of bronchopulmonary dysplasia. BMJ. 2021;375:n1974. doi:10.1136/bmj.n1974 ↩
  3. Tréluyer L, Nuytten A, Guellec I, et al. Neurodevelopment and healthcare utilisation at age 5–6 years in bronchopulmonary dysplasia: an EPIPAGE-2 cohort study. Arch Dis Child Fetal Neonatal Ed. 2024;109(1):26-33. doi:10.1136/archdischild-2023-325376 ↩
  4. Durlak W, Thébaud B. BPD: latest strategies of prevention and treatment. Neonatology. 2024;121(5):596-607. doi:10.1159/000540002 ↩
  5. Baud O, Maury L, Lebail F, et al. 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) ↩
  6. 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 ↩
  7. Pierro M, Thébaud B, Soll R. Mesenchymal stem cells for the prevention and treatment of bronchopulmonary dysplasia in preterm infants. Cochrane Database Syst Rev. 2017;(11):CD011932. doi:10.1002/14651858.CD011932.pub2 ↩
  8. Mueller M, Kramer BW. Stem cells and bronchopulmonary dysplasia—the five questions: which cells, when, in which dose, to which patients via which route? Paediatr Respir Rev. 2017;24:54-59. doi:10.1016/j.prrv.2016.12.003 ↩
  9. Ahn SY, Chang YS, Lee MH, et al. Stem cells for bronchopulmonary dysplasia in preterm infants: a randomized controlled phase II trial. Stem Cells Transl Med. 2021;10(8):1129-1137. doi:10.1002/sctm.20-0330 ↩
  10. Ahn SY, Chang YS, Lee MH, Sung SI, Kim AR, Park WS. Five-year follow-up of phase II trial of stromal cells for bronchopulmonary dysplasia. Thorax. 2023;78(11):1105-1110. doi:10.1136/thorax-2022-219622 ↩
  11. Ren Z, Xu F, Zhang X, et al. Autologous cord blood cell infusion in preterm neonates safely reduces respiratory support duration and potentially preterm complications. Stem Cells Transl Med. 2020;9(2):169-176. doi:10.1002/sctm.19-0106 ↩
  12. Ren Z, Xu F, Wei W, et al. Prevention for moderate or severe BPD with intravenous infusion of autologous cord blood mononuclear cells in very preterm infants. eClinicalMedicine. 2023;57:101844. doi:10.1016/j.eclinm.2023.101844 ↩