Could a Sleep Hormone Help Premature Babies Breathe? What a New Study Found

A plain-language look at a small trial testing melatonin given to mothers before a planned early birth, alongside the usual steroid medicine

A small study from Iran asked whether giving mothers melatonin — the natural hormone many people know as a sleep aid — in the two weeks before a planned early (premature) delivery could help their babies breathe more easily after birth. Every mother in the study also received the standard steroid injections that doctors have used for decades to strengthen a premature baby's lungs; half were given melatonin on top of that, and half were not. Fewer babies in the melatonin group developed serious breathing trouble, and among the babies who did, none in the melatonin group needed a breathing tube. These are encouraging early signals, but the study was very small, so it is best understood as a promising idea that now needs a much larger test before it could ever change care [1].

Why This Question Matters

When a baby is born early, one of the biggest immediate worries is the lungs. Babies born too soon often have not yet made enough of a slippery substance called surfactant that keeps the tiny air sacs in the lungs open. Without it, the lungs are stiff and the baby has to work very hard to breathe — a condition doctors call respiratory distress syndrome, or RDS. It can lead to further problems, and it is one of the main reasons premature babies need help in a neonatal intensive care unit.

For many years, the most important tool against this problem has been a course of steroid injections given to the mother before birth. These steroids help the baby's lungs mature faster, and large reviews of many studies have confirmed that they lower both how often RDS happens and how severe it is [2]. This treatment is now standard whenever doctors expect a premature birth. The catch is that steroids help but do not solve the problem completely — some babies still develop breathing trouble despite them. That gap is what keeps researchers looking for something extra that could be added to the steroids to give babies' lungs even more protection.

The Story Behind This Study

This particular study focused on a specific and serious pregnancy condition called placenta accreta spectrum. Normally the placenta — the organ that feeds the baby during pregnancy — attaches loosely to the wall of the womb and separates easily after birth. In placenta accreta spectrum, it grows too deeply into the womb wall, which can cause dangerous bleeding at delivery [3]. Because of that risk, doctors usually plan a cesarean delivery a few weeks early rather than waiting for labour. Today this condition can often be spotted ahead of time with ultrasound, so the delivery date can be scheduled in advance [4]. That scheduling is what gave researchers an opportunity: a predictable two-week window before birth in which a mother could take a daily medicine.

Why melatonin? Beyond helping with sleep, melatonin is a powerful natural antioxidant, meaning it helps mop up the kind of cell damage and inflammation that can harm delicate newborn lungs [5]. Earlier research had found that giving melatonin directly to premature babies could calm inflammation and improve their breathing when they already had RDS [6], and another study suggested it might reduce a chronic lung problem of prematurity [7]. Most of that earlier work involved giving melatonin to the baby after birth. What made this study different — and new — was the idea of giving it to the mother beforehand, so it could reach the baby through the placenta before the lungs were ever challenged.

What the Researchers Did and Found

The researchers enrolled 64 pregnant women with placenta accreta spectrum at a single hospital in Tehran, all delivering at around 32 to 34 weeks of pregnancy. The women were randomly split into two groups. One group took melatonin, 10 milligrams a day, for two weeks before their scheduled cesarean, in addition to the standard steroid injections. The other group received the steroid injections alone. After a few families left the study, 30 women in each group were included in the final results [1].

The main thing the researchers measured was how many babies developed RDS. In the melatonin group, 5 out of 30 babies (about 17 in 100) developed it, compared with 9 out of 30 (30 in 100) in the group that got steroids alone. That is a meaningful-looking drop, but because the study was small, the numbers were not different enough to rule out chance — in plain terms, the study simply did not include enough babies to prove that melatonin was responsible for the difference [1].

The most eye-catching result was about breathing tubes. Among the babies who did develop RDS, none of the 5 in the melatonin group needed to be put on a ventilator through a breathing tube, while 6 of the 9 affected babies in the other group did. This difference was large enough to be statistically meaningful. The babies in the melatonin group also tended to have slightly better scores at birth and shorter hospital stays, though those differences could have been due to chance. Importantly, no harmful effects from the melatonin were seen in the mothers or babies [8].

How to Read These Results

It is worth being honest about how small this study was. The striking "no breathing tubes" finding came from comparing just 5 babies with 9 babies. With numbers that small, even one or two babies turning out differently could have changed the result completely. That is why the researchers themselves were careful to say their study points to a possibility rather than proving anything. Encouraging early results like these are exactly how good medical research begins — but they are a starting point, not a conclusion. The study was also done at a single hospital, in mothers with one particular condition, so it cannot tell us how melatonin would work for other premature babies.

It also helps to understand why the breathing-tube finding caught researchers' attention even though it was based on so few babies. When a premature baby with RDS cannot get enough oxygen with gentler support, doctors may place a tube into the windpipe and connect it to a ventilator that breathes for the baby. This is life-saving and routine, but it is also more invasive than gentler forms of breathing support, and avoiding it when possible is generally better for a fragile newborn. So a hint that melatonin-exposed babies might avoid the tube is exactly the kind of outcome worth chasing — it points at a benefit that would matter in daily life for families and babies, not just a number on a chart. The reason to stay cautious is not that the outcome is unimportant, but that five and nine babies are simply too few to be sure the pattern is real rather than luck [1].

For families, the most important takeaway is that this does not change today's care. The proven, recommended treatment before a premature birth is still the steroid course, and this study does not suggest replacing or skipping it [2]. Melatonin here was an add-on being tested for the first time in this way, not an established treatment. If you are pregnant, this study is also not a reason to start taking melatonin on your own. While human studies so far suggest melatonin is generally safe in pregnancy [8], one animal study raised concerns in a specific situation involving poorly growing babies [9], and any medicine or supplement during pregnancy should only be taken with your doctor's guidance.

What Comes Next

The researchers who ran this study, and others in the field, agree on what needs to happen: a much larger trial, run at several hospitals, with babies randomly assigned in a way that keeps the comparison as fair as possible [10]. A bigger study could finally answer whether antenatal melatonin truly helps premature babies' lungs, whether it works at earlier stages of prematurity, and whether it is completely safe. The broader body of research on melatonin and breathing problems is promising enough that scientists believe this question is worth answering properly [11]. A larger study would also let researchers measure the things that matter most to families in more detail — how long babies need help breathing, how much extra oxygen they require, and how they do in the weeks and months after they go home. Because melatonin has also been studied for protecting the newborn brain, future trials may look at more than just the lungs, following children over time to see whether there are any longer-term benefits or risks. Answering those questions properly takes time and careful work, which is exactly why the researchers were careful not to overstate what their small study showed.

For now, the honest summary is a hopeful one: a familiar, inexpensive, generally safe substance has shown an early hint of benefit, and researchers are working to find out whether that hint holds up. If you or someone you love is facing a premature birth, the reassuring reality is that today's standard care — the steroid injections and an experienced neonatal team ready to support your baby's breathing — is well established and effective, and any new idea like this one will be tested thoroughly before it becomes part of that care.

References

  1. Ghotbizadeh Vahdani F, Haddadi M, Ahmadi S, et al. Efficacy of Melatonin Administration in Pregnancy in Prevention of Neonatal Respiratory Distress Syndrome in Preterm Neonates: A Randomized Controlled Trial. J Family Reprod Health. 2025;19(3):240–246. doi:10.18502/jfrh.v19i3.20063 ↩
  2. Roberts D, Brown J, Medley N, Dalziel SR. Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth. Cochrane Database Syst Rev. 2017;3(3):CD004454. doi:10.1002/14651858.CD004454.pub3 ↩
  3. American College of Obstetricians and Gynecologists, Society for Maternal-Fetal Medicine. Obstetric care consensus No. 7: placenta accreta spectrum. Obstet Gynecol. 2018;132(6):e259–75. doi:10.1097/AOG.0000000000002983 ↩
  4. Shainker SA, Coleman B, Timor-Tritsch IE, et al. Special Report of the SMFM Placenta Accreta Spectrum Ultrasound Marker Task Force. Am J Obstet Gynecol. 2021;224(1):B2–B14. doi:10.1016/j.ajog.2020.09.001 ↩
  5. Reiter RJ, Calvo JR, Karbownik M, Qi W, Tan DX. Melatonin and its relation to the immune system and inflammation. Ann N Y Acad Sci. 2000;917:376–86. doi:10.1111/j.1749-6632.2000.tb05402.x ↩
  6. Gitto E, Reiter RJ, Cordaro SP, et al. Oxidative and inflammatory parameters in respiratory distress syndrome of preterm newborns: beneficial effects of melatonin. Am J Perinatol. 2004;21(4):209–16. doi:10.1055/s-2004-828610 ↩
  7. Gharehbaghi MM, Yeganedoust S, Shaseb E, Fekri M. Evaluation of melatonin efficacy in prevention of bronchopulmonary dysplasia in preterm newborn infants. Turk J Pediatr. 2022;64(1):79–84. doi:10.24953/turkjped.2021.1334 ↩
  8. Vine T, Brown GM, Frey BN. Melatonin use during pregnancy and lactation: a scoping review of human studies. Braz J Psychiatry. 2022;44(3):342–8. doi:10.1590/1516-4446-2021-2156 ↩
  9. González-Candia A, Veliz M, Araya C, et al. Potential adverse effects of antenatal melatonin as a treatment for intrauterine growth restriction: findings in pregnant sheep. Am J Obstet Gynecol. 2016;215(2):245.e1–7. doi:10.1016/j.ajog.2016.02.040 ↩
  10. Lee JY, Na Q, Shin NE, et al. Melatonin for prevention of fetal lung injury associated with intrauterine inflammation and for improvement of lung maturation. J Pineal Res. 2020;69(3):e12687. doi:10.1111/jpi.12687 ↩
  11. Habtemariam S, Daglia M, Sureda A, et al. Melatonin and respiratory diseases: a review. Curr Top Med Chem. 2017;17(4):467–88. doi:10.2174/1568026616666160824120338 ↩