Clinical deterioration after steroid tapering or discontinuation in very-low-birth-weight infants: association with small-for-gestational-age status

In the fragile world of neonatal intensive care, where tiny infants born weeks before their due date fight to survive, doctors often turn to powerful medicines to help their lungs grow and their bodies stabilize. Among these tools are systemic steroids, a type of hormone therapy that reduces inflammation and helps the body manage stress. For the smallest babies, those weighing less than 1,500 grams at birth, these drugs can be a lifeline, allowing them to breathe easier and wean off ventilators. However, like many potent treatments, steroids come with a catch. When a baby's body has relied on an external supply of hormones for a while, its own natural production system can go quiet. This is similar to how a muscle might weaken if it is supported by a brace for too long; once the brace is removed, the muscle may struggle to bear weight immediately. In the case of these infants, when doctors begin to lower the dose of the medicine or stop it entirely, the baby's own adrenal glands—small organs that sit atop the kidneys and are responsible for making natural stress hormones—may not wake up fast enough. This lag can lead to a sudden drop in blood pressure, low blood sugar, or trouble breathing, a situation that looks very much like the body running out of fuel.

For years, medical teams have watched for these signs of decline, but the reasons why some babies crash while others recover smoothly have remained unclear. Is it the amount of medicine given? How long the treatment lasted? Or is there something about the baby's own development that makes them more vulnerable? A team of researchers at Oita University in Japan set out to answer these questions by looking closely at the records of very-low-birth-weight infants who had received steroid therapy. They wanted to understand what happened when the medicine was tapered down or stopped, and specifically, which babies were at the highest risk of getting sick again during this critical transition.

The researchers examined the medical histories of sixty-two tiny infants admitted to their hospital between 2017 and 2023. Of these, twenty-six had received systemic steroids to treat conditions like severe lung disease or low blood pressure. The team defined "clinical deterioration" as a specific set of warning signs appearing within two weeks of reducing or stopping the drug. These signs included low blood pressure, low urine output, imbalanced salts in the blood, low blood sugar, or new episodes of stopped breathing. They found that nine of the twenty-six treated infants, or about thirty-five percent, experienced this kind of decline. The researchers then compared the babies who got sick after the drug was reduced with those who did not, looking for any differences in their birth history, their mothers' health, or the details of their steroid treatment.

The results pointed to a single, surprising factor that stood out above all others. The babies who deteriorated were significantly more likely to be small for their gestational age. In medical terms, this means they were born weighing less than the tenth percentile for how many weeks they had been in the womb; they were smaller than expected for their age. Six of the nine babies who got sick after the steroid was reduced were small for their age, representing sixty-seven percent of that group. In contrast, among the seventeen babies who did not get sick, only four were small for their age. When the researchers ran statistical tests to see if this was a coincidence or a real link, the numbers confirmed that being small for gestational age was an independent risk factor. The odds of a small-for-gestational-age baby developing these complications were more than six times higher than for a baby of normal size for their age.

Interestingly, the study found that the specific details of the steroid treatment did not seem to be the deciding factor. Whether the baby had received a higher dose, a longer course of treatment, or a faster reduction in the medicine did not predict who would get sick. This suggests that the vulnerability lies not in how the drug was given, but in the baby's own biological makeup. The researchers also noticed a distinct difference in when the trouble started. Among the six small-for-gestational-age babies who deteriorated, five of them got sick two to seven days after the steroid was completely stopped. In contrast, all three of the babies who were a normal size for their age and still got sick experienced their decline while the doctors were still slowly reducing the dose, before the medicine was fully gone.

This timing difference offers a clue about what is happening inside the body. The babies of normal size seemed to struggle while the external support was still being withdrawn, perhaps needing a little more time to adjust as the dose dropped. The small-for-gestational-age babies, however, appeared to hold on until the medicine was gone, only to falter once the external supply was completely cut off. This delay might indicate that their own adrenal glands are slower to wake up or less capable of producing enough hormone on their own, a condition that becomes apparent only when the external help is fully removed. In every case where a baby deteriorated, the medical team was able to reverse the situation by giving the steroid medicine again or increasing the dose, and the infants improved.

The study concludes that being small for gestational age is a key warning sign for doctors to watch. While the treatment for lung disease or low blood pressure remains necessary, the findings suggest that the most careful monitoring should happen in the week following the complete stop of the medication, especially for those infants who were born smaller than expected for their age. The researchers acknowledge that their study was limited by its small size and the fact that it looked back at past records, so they cannot yet say exactly why the small-for-gestational-age babies are more vulnerable. They suspect it may be related to how the stress-hormone system develops in the womb when growth is restricted, but they emphasize that future studies are needed to confirm this. For now, the message is clear: when the medicine stops, the smallest babies may need the most careful watch.