Preemies get a growth boost with prenatal steroids

Administering corticosteroids during pregnancy leads to improved postnatal growth in infants born extremely or very preterm, as shown in a study.

In a cohort of 11,912 maternal-infant dyads, neonates with antenatal corticosteroid exposure had significantly lower trajectory percentile for weight (53.1 vs 58.7; p<0.001), length (51.5 vs 59.3; p<0.001), and head circumference (52.8 vs 63.2; p<0.001) at birth compared with their counterparts who had no such exposure. [Chou FS, et al, PAS 2024]

By the time of discharge, neonates in the exposed group had caught up to those in the unexposed group, showing no significant difference in the trajectory percentile for weight (54.9 vs 52.2; p<0.119), length (49.1 vs 49.9; p<0.686), and head circumference (42.1 vs 39.7; p<0.107), Chou added.

“In a multivariable regression analysis, we found that antenatal corticosteroid use was significantly associated with better postnatal growth, as demonstrated by increases in trajectory percentile [for all three parameters examined] in the exposed group,” he pointed out.

Further analysis indicated that the benefit of antenatal corticosteroids for postnatal growth was more pronounced among infants born at higher gestational age (27-29 vs 23-24 and 25-26 wk) and only observed among infants without exposure to hypertensive disorders of pregnancy (pre-eclampsia, eclampsia, or HELLP syndrome) and those without fetal growth restriction.

These findings, according to Chou, can inform discussions with pregnant women about the use of antenatal corticosteroids.

Already, antenatal corticosteroids are widely used by doctors in the US and globally to improve neonatal outcomes. They have been shown to significantly reduce infant deaths and complications such as respiratory distress syndrome, intraventricular hemorrhage, and necrotizing enterocolitis, Chou said. Current clinical guidelines recommend giving corticosteroids for pregnant mothers at risk of preterm birth.

Nevertheless, Chou also noted that antenatal corticosteroids can lead to reduced foetal growth, with the effect seemingly persisting throughout gestation.

For their study, Chou and his team used retrospective data from Pediatrix Clinical Data Warehouse and identified mothers between 18–40 years old who gave birth to infants at a gestational age of between 23 and 29 weeks. Of the mothers, 88 percent received antenatal corticosteroids (mean age 28.9 years, 37.2 percent White, 9.8 percent had obesity, 10.7 percent had gestational diabetes) while the remaining 12 percent did not (mean age 28.8 years, 36.3 percent White, 8.5 percent had obesity, 10.1 percent had gestational diabetes). The team developed Postnatal Growth Charts for Preterm Infants and used them to assess postnatal growth. [https://nicugrowth.app]

The study had several limitations, including its retrospective nature and the possibility of residual confounding due to noticeable differences in maternal characteristics between the exposed and unexposed groups. Data on antenatal corticosteroid dosing, course, and timing were not available, and the accuracy of measurements could not be verified.

“Prospective studies are needed to verify our findings. But this may not be feasible because the use of antenatal corticosteroids has become standard of care,” Chou said.