Effects of Antenatal Corticosteroids on Regional Brain and Non-neural Tissue Water Content in the Ovine Fetus

Abstract

Objective: We examined the effects of maternal corticosteroid administration on water content in regional tissue in ovine fetuses at 60%, 80%, and 90% of gestation.

Methods: After catheters were placed in the fetuses, the ewes were given four 6-mg doses of dexamethasone or placebo injections 12 hours apart over 48 hours. Water conent of fetal tissue was determined 18 hours after the last injection was given to the ewes. Tissue water ws determined by wet-to-dry weight ratio in brain (cerebral cortex, caudate nucleus, cerebellum, midbrain, and medulla) and non-neural tissues (kidney, liver, muscle, and skin) at each gestational age.

Results: Water content (P < .05) in brain regions was lower in fetuses from dexamethasone-treated than placebo-treated ewes at 60% but not 80% or 90% of gestation and in non-neural tissues at each gestational age.

Conclusion: Maternal treatmet with a contricosteroid regimen similar to that used in the clinical setting was associated with small decreases in brain water content early but not later in gestation. This corticosteroid treatment regimen was also associated with decreased regional non-neural tissue water content at 60%, 80%, and 90% of gestation.