Antenatal Betamethasone Compared With Dexamethasone In Terms Of Fetal Heart Rate Variability And Fetal Body Movements

Abstract

Aim: Preterm labor occurs between 20th and 37th gestational week which is regardless of the birth weight. The incidence of preterm birth is increasing and continues to be the leading cause of neonatal mortality and morbidity. Antenatal corticosteroids are used for pregnant women at risk of preterm labor to reduce fetal mortality and morbidity by increasing fetal lung maturation and preventing the fetus from respiratory distress syndrome. In this study, we aimed to evaluate the effects of antenatal dexamethasone and betamethasone on fetal heart rate variability and fetal body movements. Material and method: The pregnant women applied to clinic due to the risk of preterm labor between November 2003 and May 2004 hospitalised due to the risk of preterm labor and tocolytic treatment. The glucocorticoids to be initiated and to provide lung maturation were included in the study. Included in the study pregnant women were randomly divided into two groups. 24 hours for 20 pregnant women in the first group, 12 mg betamethasone was administered intramuscularly. 20 in the second group 6 mg dexamethasone was administered intramuscularly every 12 hours. NSTs for later evaluation of fetal well-being and baby movements were compared. Results : Pregnant women in betamethasone and dexamethasone groups compared in terms of age, gravida, parity and gestational week, there was no significant difference between the two groups (p> 0.05). At the time of first glucocorticoid application (onset) and 24 hours after the last dose of betamethasone / dexamethasone therapy, fetal heart rate, acceleration, deceleration and fetal movement counts were calculated for 3 days in the morning and evening. A significant increase was observed at heart rate in the betamethasone group after treatment, but there was no change in basal heart rate in the dexamethasone group. In the number of acceleration; significant increase was observed in betamethasone group while there was no statistically significant change was observed in the dexamethasone group. Fetal body movements were changed significantly in both groups compared with the basal movements. Conclusion: Antenatal glucocorticoid application (especially betamethasone) caused a temporary suppression in the NST and fetal movements that were used to determine fetal well-being. It should be kept in mind that these temporary changes may be misdiagnosed as fetal distress. Both dexamethasone and betamethasone can be applied in preterm delivery as a safe manner.