The study of the relationship between the time interval from antenatal corticosteroid administration until preterm birth and the occurrence of respiratory morbidity by Wilms et al makes an interesting reading. The study results consolidate the available evidence, which might compel us to take a relook at the outcome of repeated-dose antenatal steroid (AS) regimens. Most importantly, the study reemphasizes the short-term efficacy of antenatal steroid use in pregnant women. However, as per the authors’ assumption, endotracheal intubation by itself should not be considered equivalent to respiratory morbidity, because preterm infants may require intubation for a variety of indications, including apnea, sepsis, meningitis, intraventricular bleed, etc.

Babies delivered after multiple courses of corticosteroids and those delivered within 7 days of dosing demonstrate improved respiratory compliance when compared with untreated and remotely treated infants. As shown previously by Ring et al, a time interval of more than 14 days is associated with an increased risk for ventilatory support and surfactant use in neonates who are delivered at longer than 28 weeks’ gestation. Combining these 2 observations, it seems likely that babies who are delivered within 7 days of antenatal steroids fare better than those who are delivered after 7 or more days, irrespective of single or multiple courses of steroids.

The present study rekindles the curious question of whether targeted and rescue-course corticosteroids are all that is needed to provide a balanced protection for the immature fetuses after birth, rather than the actual number of steroid doses. A benefit in composite morbidity and a decrease in the presence and severity of respiratory distress syndrome has already been noted with such a strategy. It has also been suggested that the enzyme system responsible for surfactant production can be repetitively induced, despite prior treatment with AS; but repeated doses of steroids have deleterious effects on fetal development.

The message now seems loud and clear: the time between the last dose of antenatal corticosteroids and delivery is the key, and it should be at least 24 hours and within 7 days of delivery. The significant heterogeneity in the results of previous multiple-course corticosteroid studies can be accounted for by a similar explanation. Therefore, future research should aim at finding clinical and laboratory tools that better equip the obstetricians to improve the sensitivity and specificity of clinical judgment and predicting the mothers who might deliver at least 24 hours later, within the next 7 days, and before 34 weeks’ gestation.