A placebo-controlled comparison between betamethasone and dexamethasone for fetal maturation: differences in neurobehavioral development of mice offspring.

OBJECTIVE: Our purpose was to determine whether antenatal betamethasone or dexamethasone is the preferred drug by use of neurobehavioral development assessment of exposed mice offspring. STUDY
DESIGN: Thirty adult CD-1 mice were randomly assigned to one of three groups (n = 10) to be administered a single subcutaneous dose of either a placebo (0.9% sodium chloride), betamethasone (0.10 mg), or dexamethasone (0.10 mg) on day 14 (74%) of gestation. The offspring then performed a battery of sensory, motor, motivational-anxiety, cognitive, and social tasks. Data were compared with use of analysis of variance, Kruskal-Wallis, or chi2 testing where appropriate.
RESULTS: The offspring from the three treatment groups were indistinguishable at birth. Dexamethasone exposure induced a brief developmental delay. Separation anxiety was increased in the dexamethasone-exposed group in the perinatal period, whereas exposure to both corticosteroids decreased anxiety in the juvenile period, continuing into adulthood among male betamethasone-exposed mice. Selective enhancement of a memory process occurred in betamethasone-exposed mice, whereas dexamethasone exposure resulted in a decrement. Socialization as to place preference while awake and asleep varied among the three treatment groups. Corticosteroid treatment did not induce significant changes in sensory, motor, motivation, and learning performances or in reproductive capability and progeny development.
CONCLUSION: Subtle differences in offspring performances of neurobehavioral development tasks favored antenatal betamethasone rather than dexamethasone. This finding, along with the knowledge that dexamethasone is less potent in accelerating lung maturity in the fetal mouse, suggests that betamethasone may be the preferred corticosteroid to use when human preterm delivery is imminent.