Adverse Postnatal effects of multiple doses of Antenatal Steroids

Multiple Courses of Antenatal Steroids Not Recommended for Preterm Birth

Laurie Barclay, MD
From Medscape Medical News

December 22, 2008 — Multiple courses of antenatal steroids every 14 days do not improve preterm birth outcomes, are linked to decreased size at birth, and are therefore not recommended, according to the results of a study reported in the December 20/27 issue of The Lancet.

"One course of antenatal corticosteroids reduces the risk of respiratory distress syndrome and neonatal death," write Kellie E. Murphy, from Mount Sinai Hospital, University of Toronto in Toronto, Ontario, Canada, and colleagues from the MACS Collaborative Group.

The study sample consisted of 1,858 women at 25 to 32 weeks of gestation who were at high risk for preterm birth, who were still undelivered 14 to 21 days after an initial course of antenatal corticosteroids, and who continued to be at high risk. Participants were randomly assigned to receive multiple courses of antenatal corticosteroids (n = 937) or placebo (n = 921), every 14 days until week 33 or delivery, whichever came first.

Compared with infants exposed to placebo, those exposed to multiple courses of antenatal corticosteroids had similar morbidity and mortality rates, with the main study endpoint occurring in 150 (12.9%) vs 143 (12.5%). Compared with infants in the placebo group, those in the multiple-dose corticosteroid group had lower birth weight (2,216 vs 2,330 g; P = .0026), shorter length (44.5 vs 45.4 cm; P < .001), and smaller head circumference (31.1 vs 31.7 cm; P < .001).

"Multiple courses of antenatal corticosteroids, every 14 days, do not improve preterm-birth outcomes, and are associated with a decreased weight, length, and head circumference at birth," the study authors write. "Therefore, this treatment schedule is not recommended."

In an accompanying comment, John P. Newnham, from the School of Women's and Infants' Health, University of Western Australia in Perth, and Karen Simmer, from King Edward and Princess Margaret Hospitals in Perth, note that follow-up of the children in this study will help shed light on any long-term effects of multiple doses of antenatal corticosteroids.

"Particular attention should be paid to those areas in which other studies have suggested problems, including behaviour, growth, glucose tolerance, and blood pressure," Drs. Newnham and Simmer write. "In the meantime, the evidence suggests it is prudent for obstetricians not to prescribe repeat injections of antenatal corticosteroids. Single-course therapy is of considerable benefit, but we should be aware of the potential dangers of giving too much of a good thing."

Lancet. 2008;372:2094-2095, 2143-2151.