Preterm birth remains a significant health problem worldwide.
1,2 A single course of antenatal corticosteroid therapy is an example of a treatment that yields improved health outcomes and cost savings and is recommended for pregnant women at risk of preterm birth between 24 and 33 weeks’ gestational age.
3,4 However, 50% of women remain pregnant 7 to 14 days later, leading to the question of whether additional courses should be given to women remaining at risk for preterm birth.
5 The Multiple Courses of Antenatal Corticosteroids for Preterm Birth Study (MACS) was an international, multicenter, double-masked randomized clinical trial comparing multiple courses of antenatal corticosteroids vs a single course in women at risk for preterm birth.
6 The initial results showed that infants born to women in the multiple-courses group had a similar rate of the composite outcome as infants in the single-course group.
6 However, multiple courses were associated with reduced fetal growth.
6,7 The follow-up studies of the clinical trials on multiple/repeated courses of antenatal corticosteroids reported no significant differences in the rates of death or neurodevelopmental difficulties.
8-11 One study did note a nonsignificant increase in cerebral palsy in the multiple-courses group.
10 Animal studies evaluating the effects of corticosteroids on the developing brain have shown decreased hippocampal weight and neuron number; impairment in myelination, neurologic development, retinal maturation, and axonal myelination of optic and auditory nerves; abnormal auditory function; and altered behaviors.
12-14 Long-term follow-up for these children remains critical because short-term benefits can be offset by long-term problems as was seen by long-term studies of postnatal corticosteroid treatment in preterm infants.
15 In view of this, our primary aim was to determine the effects of single vs multiple courses of antenatal corticosteroid therapy on death or neurodevelopmental disability (neuromotor, neurosensory, or neurocognitive/neurobehavioral function) at 5 years of age. Our secondary aims were to determine the effect on height, weight, head circumference, blood pressure, intelligence, and specific cognitive (visual, spatial, and language) skills.