Infants born prematurely after exposure to antenatal corticosteroids may face a slightly higher risk of long-term respiratory illness, a finding that could be particularly relevant for pregnancies complicated by fetal and neonatal alloimmune thrombocytopenia (FNAIT), according to a large population-based study presented recently at the SMFM 2026 Pregnancy Meeting.
Researchers reported that steroid exposure before 34 weeks of pregnancy was independently associated with increased respiratory problems throughout childhood and adolescence.
Antenatal corticosteroids are commonly given to pregnant patients who may deliver early because the drugs help accelerate fetal lung development and reduce immediate newborn complications. These medications can also be used in complex pregnancies, including some involving FNAIT, when doctors anticipate early delivery to protect the fetus from bleeding risks.
To better understand long-term outcomes, investigators conducted a retrospective population-based cohort study of all singleton preterm births at a tertiary medical center. The analysis included 13,580 infants born before 37 weeks. Among them, 1,538 children (11.3%) were exposed to antenatal corticosteroids before 34 gestational weeks. Researchers tracked respiratory diagnoses in both community and hospital records from birth through age 18.
Read more about the prognosis of FNAIT
Infants who received steroid exposure before birth were delivered earlier on average, at 32.6 weeks compared with 34.2 weeks in unexposed infants. Their mothers also had higher rates of cesarean delivery and pregnancy-related hypertensive disorders.
“These findings underscore the importance of long-term follow-up in ACS [antenatal corticosteroids]-exposed children,” explained the investigators who conducted this research.
When researchers examined long-term health outcomes, respiratory morbidity occurred more often in the exposed group, with an incidence of 161.8 cases per 1,000 person-years compared with 68.8 per 1,000 person-years in the unexposed group. Diagnoses included asthma and obstructive sleep apnea.
Kaplan–Meier analysis showed that cumulative respiratory illness was significantly higher among children exposed to antenatal corticosteroids. The strongest association appeared in infants born before 28 weeks of gestation. After adjusting for gestational age at birth, maternal age, diabetes mellitus, hypertensive disorders of pregnancy and cesarean delivery, steroid exposure still remained linked to increased respiratory risk.
For families managing FNAIT, the findings do not suggest that antenatal corticosteroids should be avoided. Instead, they emphasize the need for long-term follow-up. These medications remain an important tool for improving survival and early health in premature infants, including those born after pregnancies complicated by FNAIT. However, clinicians and parents may want to monitor children exposed to these treatments more closely for breathing conditions such as asthma as they grow.
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