The likelihood of preterm delivery and also the gestational age need to be carefully considered when contemplating the use of antenatal corticosteroid therapy among pregnant women. The efficacy of such therapy is highest when the course is given 24 hours to 7 days prior to delivery. Administration more than 7 days before delivery leads to reduced benefit and potentially unnecessary adverse effects . Trials enrolling pregnant women from 24 + 0 to 34 + 6 weeks gestation at high risk of preterm birth show that antenatal corticosteroid therapy significantly reduces perinatal death, respiratory distress syndrome, and intraventricular hemorrhage in the infants who in fact delivered pre-term. Evidence from cohort studies shows a significant reduction in perinatal mortality among infants exposed to antenatal corticosteroid therapy at less than 24 weeks gestation. Women between 22 + 0 weeks and 23 + 6 weeks gestation at high risk of preterm birth within the next 7 days should be provided with a multidisciplinary consultation regarding the high likelihood for severe perinatal morbidity and mortality, and associated maternal morbidity. Steroids should be given if intensive care for the baby is planned. For more information:
Asztalos E, Willan A, Murphy K, et al. Association between gestational age at birth, antenatal corticosteroids, and outcomes at 5 years: multiple courses of antenatal corticosteroids for preterm birth study at 5 years of age (MACS-5). BMC Pregnancy Childbirth 2014;14:272. PMID: 25123162.
Roberts D, Dalziel S. Antenatal corticosteroids for accelerating fetal lung maturation for women at risk of preterm birth. Cochrane Database Syst Rev 2006;(3):CD004454. PMID: 16856047.
Skoll A, Boutin A, Bujold E, Burrows J, Crane J, Geary M, Jain V, Lacaze-Masmonteil T, Liauw J, Mundle W, Murphy K, Wong S, Joseph KS. No. 364-Antenatal Corticosteroid Therapy for Improving Neonatal Outcomes. J Obstet Gynaecol Can 2018;40(9):1219-1239. PMID: 30268316.