Effects of betamethasone on the fetuses and placentas of female albino rats - Revista Brasileira de Ginecologia e Obstetrícia

Purpose: to analyze the effect of betamethasone on the pregnancy of rats. Methods: thirty pregnant rats were divided into three groups of ten animals each. Group I — the animals received betamethasone IM (1 mg/kg body weight, in 0.5 ml distilled water) on the 11th, 12th, 18th and 19th day of pregnancy. Group II — the rats received distilled water (0.5 ml) IM on the 11th, 12th, 18th and 19th day of pregnancy. Group III – the rats did not receive any drug or vehicle. The animals were weighed on days 0, 7, 14 and on the 20th of pregnancy, and on the last day of weighing, the animals were sacrificed. The number of implantations, resorptions, fetuses, placentas, malformations, maternal and fetal mortality as well as the weight of the fetuses and placentas were obtained and analyzed. Results: our results show that the rats treated with betamethasone gained significantly less weight. Their fetuses had an average weight of 3.2 g compared with 3.75 g in the control group. The results regarding placental weight were 0.36 g vs 0.48 g, respectively. All these differences were statistically significant. Conclusions: betamethasone had a negative effect on the gain of weight of matrices, fetuses and placentas when administered repeatedly and continuousy after the second half of pregnancy.