When pregnant women are at high risk for preterm birth, giving them a single injection of corticosteroids has been shown to reduce the babyâ€™s chances of having serious lung problems after birth.
But some women receive multiple injections of corticosteroids, and a new study shows that repeat courses of corticosteroids are linked to an increased rate of cerebral palsy among children of these mothers.
The researchers followed women between 23 weeks and 32 weeks pregnant who remained pregnant after an initial dose of corticosteroids. They were randomly assigned to receive weekly courses of the corticosteriod betamethasone or placebo injections.
Children born to women enrolled in the study were given physical and neurological examinations at ages 2 to 3 years old. A total of 556 children were examined. Of these, 486 (87.4 percent) had physical exams and 465 (83.6 percent) were evaluated for brain function using a measurement tool called the Bayley Scales of Infant Development.
The researchers found that there were no meaningful differences in weight, head circumference or Bayley scores between children whose mothers received a single dose of corticosteroids. However, six children in the group whose mothers received multiple injections had cerebral palsy, compared to only one child in the placebo group.
The other study reached similar results, with one key difference: the researchers found smaller head sizes among the infants exposed to repeat courses of corticosteroids.
Both studies found that repeat courses produced better results than single courses in terms of reducing lung problems in the infants. However, both studies also found lower birth weights in the infants exposed to repeat courses.