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 betamethason e or dexamethasone is the preferred drug by use of neurobehavioral dev elopment assessment of exposed mice offspring. STUDY DESIGN: Thirty ad ult CD-1 mice were randomly assigned to one of three groups (n = 10) t o 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, o r chi(2) testing where appropriate. RESULTS: The offspring from the th ree treatment groups were indistinguishable at birth. Dexamethasone ex posure induced a brief developmental delay. Separation anxiety was inc reased in the dexamethasone-exposed group in the perinatal period, whe reas exposure to both corticosteroids decreased anxiety in the juvenil e period, continuing into adulthood among male betamethasone-exposed m ice. Selective enhancement of a memory process occurred in betamethaso ne-exposed mice, whereas dexamethasone exposure resulted in a decremen t. Socialization as to place preference while awake and asleep varied among the three treatment groups. Corticosteroid treatment did not ind uce significant changes in sensory, motor, motivation, and learning pe rformances or in reproductive capability and progeny development. CONC LUSION: Subtle differences in offspring performances of neurobehaviora l development tasks favored antenatal betamethasone rather than dexame thasone. 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 hu man preterm delivery is imminent.