OP-009 Antenatal corticosteroids in the late preterm: a five year retrospective comparative study

Late preterm neonates, although of comparable size and weight to term newborns, are still at higher risk for morbidities and mortality compared to term infants. However, ANC use to prevent these complications in the late preterm remains controversial. The goal of this study was to evaluate the outcomes of late preterm neonates who received primary and/or rescue courses of ANC within or beyond seven days compared to those who did not receive antenatal corticosteroids.

Eighty one mothers and babies were included in this study. Review of their medical records was done. Patients were grouped into four: Group 1 – those who delivered without being given ANC; Group 2 - delivered between 34 – 36 6/7 weeks AOG and were given primary course of ANC; Group 3 - had history of preterm labor and given ANC prior to 34 weeks but delivered between 34 – 36 6/7 weeks AOG and given rescue course of ANC; and Group 4 - had history of preterm labor prior and given ANC prior to 34 weeks but delivered between 34 – 36 6/7 weeks AOG and not given rescue course.

There was no significant difference in the mean Apgar score at the first (p=0.538) and fifth minute (p=0.741), prevalence of respiratory distress syndrome (p=0.201) and intraventricular hemorrhage (p=0.235) across the four groups. Prevalence of the need for surfactant was significantly highest in Group 4 (50.0%) and lowest in Group 3 (6.2%) (p=0.004) while the prevalence of neonatal hypoglycemia was significantly highest in Group 4 (80.0%) and lowest in group 1 (11.1%) (p<0.001). The benefits and adverse effects of ANC in the late preterm group should be further studied. The additional benefit of reduced need for surfactant is modest and did not affect the primary clinical endpoint of reduced risk for respiratory distress. The neonatal outcomes depending on the timing of administration of ANC (delivered within or more than seven days) did not differ significantly.

The benefits, outcomes and long term maternal and neonatal effects of ANC given in the late preterm should be further studied. Based on literature, ANC seems to be beneficial in the late preterm at 34 - 35 6/7 weeks AOG but respiratory distress at 36 weeks and early term may result from complications during the prenatal to postnatal transition period. At this age of gestation, starting 36 weeks and beyond, ANC does not seem to be beneficial anymore, given the potential risk for neonatal hypoglycemia as well. In addition, the benefit of reduced need for surfactant among those given rescue course in the late preterm seen in this study is modest and cannot yet be confirmed with the small sample size and the retrospective design of the study.