The short-term (0 -48 h) effects of maternal betamethasone administration on computerized fetal heart rate (FHR) parameters were studied in 36 pregnancies at increased risk for preterm delivery. FHR was recorded for 90 min immediately before the start of betamethasone treatment and again at 6-h intervals during the next 48 h. Multiple linear regression models were used to assess the possible effects on FHR parameters of gestational age, time of day, clinical indication for treatment, and use of tocolytic drugs. Within 12 h after the start of treatment, significant increases occurred in FHR accelerations, and short-and long-term FHR variability (36%, 28%, and 22%, respectively), whereas basal FHR showed a 5% decrease. FHR variability was decreased by 10% at 42-48 h. The observed changes were more pronounced in older (29 -33 wk of gestation) compared with younger fetuses (25-28 wk of gestation). Decelerations occurred only in 4 out of 11 compromised fetuses during betamethasone therapy. We conclude that there are significant changes in FHR parameters during the first 48 h after betamethasone administration. These changes are transient in normal fetuses. However, the compromised fetus may be adversely affected by betamethasone. Abbreviations ACC, number of fetal heart rate accelerations FHR, fetal heart rate LTV, long-term variability STV, short-term variability Antenatal corticosteroid administration to pregnant women with threatened preterm delivery has proven to successfully reduce the risk of sequelae of prematurity, such as the respiratory distress syndrome (1,2). Recent findings in the fetus and neonate have focused attention on a variety of extrapulmonary effects of corticosteroids, including side effects on metabolic, endocrine, immunologic, cardiovascular, and CNS function (3-10). Maternal betamethasone administration has been described to transiently reduce fetal movements and heart rate variability, which are commonly used as indicators of the fetal condition (5-10). The reductions were most profound 48 -72 h after the first of two injections of betamethasone (doses 24 h apart) in studies that comprised 1-h recordings made on each of five successive days.Betamethasone readily crosses the placenta and fetal levels keep pace with the rapidly increasing maternal levels during the first few hours after administration of this drug (11). It may, therefore, be anticipated that betamethasone already exerts an effect on the fetus shortly after injection to the mother. However, the few studies that have reported on early effects of betamethasone showed an increase in FHR variability, an increase or decrease in basal FHR, or no change at all in either parameter when data were obtained within 24 h postinjection (5,6,8,10).The present study was designed to study the temporal effect of maternal betamethasone administration on various FHR parameters at 6-h intervals during the first 48 h after the initiation of treatment. We took into account the possible influences of the time of day at which betamethasone was adminis...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.