Effect of Betamethasone on Pregnant Rats: Impact on Corticosterone Level and Maternal and Fetal Adrenal Glands - Revista Brasileira de Ginecologia e Obstetrícia

Purpose: the repetitive use of antenatal corticosteroid therapy for acceleration of fetal lung maturation has been common in cases at risk of preterm delivery. We studied the corticosterone levels at term and the morphologic aspects in the maternal and fetal adrenal glands submitted to the effect of betamethasone in the second half of rat pregnancy in order to verify its consequences. Methods: thirty female pregnant rats were divided into three groups of ten animals each. Group I received betamethasone on the 11th, 12th, 18th and 19th day of pregnancy. Group II received distilled water on the same days (control group). Group III did not receive any drug (stress control group). All rats were sacrificed on the 20th day of pregnancy when plasma corticosterone levels of dams were assessed and the maternal and fetal adrenal glands were studied by light microscopy. Results: plasma corticosterone level of dams was lower in the group treated with betamethasone (4.8 mg/dL) when compared with the control groups (17.7 and 26.8 mg/dL). The light microscopy study revealed cytoplasmatic vacuolation in the fasciculate zone in the maternal and fetal adrenal glands, which indicates adrenal suppression. Conclusions: the antenatal repetitive and prolonged use of corticosteroids in pregnant rats for acceleration of lung fetal maturation causes maternal and fetal adrenal suppression.