Effect of Betamethasone Administration on Fetal Heart Rate Tracing: A Blinded Longitudinal Study

Abstract

Objective: Computerized fetal heart rate (FHR) analysis revealed that antenatal corticosteroids transiently suppress multiple parameters of fetal well-being, potentially leading to the erroneous diagnosis of fetal distress and to unnecessary iatrogenic delivery of premature infants. Our aim was to determine whether clinicians who visually analyze FHR tracings detect these suppressive effects, thereby potentially affecting their clinical management decisions. Methods: Singleton pregnancies admitted for preterm labor between 26 and 34 weeks’ gestation received two doses of betamethasone, 24 h apart, and were monitored daily between 16:00 and 19:00 h for 5 days. FHR tracings were randomly coded and presented in a non-consecutive order to four clinicians, who were unaware of the time of steroid administration. FHR baseline, FHR variability, number of accelerations and amplitude of maximal FHR acceleration were determined. Variability was scored semiquantitatively based on a modified Hon score. Analysis of variance (ANOVA) with repeated measures was used for primary analysis and followed up with the Wald test of significance. Corrections for multiple comparisons were made and only p < 0.005 considered significant. ANOVA was also used to assess the uniformity of trend in the interpretation by the four examiners for each given day. Results: Baseline FHR was elevated, FHR variability was decreased, and the number of accelerations decreased on day 1 (p < 0.0001; p < 0.0001; p < 0.0001) and day 2 (p > 0.0001; p < 0.0001; p < 0.0001) in comparison to day 0. On day 3, the FHR baseline, variability and number of accelerations returned to pre-exposure values (p = NS). The maximal amplitude of FHR accelerations showed a trend towards reduction (p = 0.08). Subgroup analysis by gestational age (group I = 26–30 weeks and group II = 30–34 weeks) showed the same response patterns and significance levels for both groups. Conclusions: Betamethasone causes profound, but transient, suppression of FHR parameters, which can mimic fetal distress. This effect is clinically recognized by visual FHR analysis. Clinicians need to be aware of this phenomenon, in order to avoid unwarranted iatrogenic delivery.

The Influence of Corticosteroids on Fetal Heart Rate Variability

“…13,24 The suppression in fHR parameters is not only visible with computerized analysis, but also detected by visual analysis of CTG tracings by clinicians. 44 In Figures 1 and 2, the decrease in fHRV after corticosteroid administration is illustrated in the case of a 29-week fetus before and 2 days after betamethasone administration.…”

RETIRED: Diagnosis, Evaluation, and Management of the Hypertensive Disorders of Pregnancy

“…Clinicians should administer corticosteroids to those women whom they feel are at high risk of delivery within a week. Antenatal corticosteroids may cause significant, transient changes in FHR and variability up to 4 days after administration [363][364][365].…”

Intramuscular Fetal Corticosteroid Therapy: Short-Term Effects on the Fetus

“…However, the decrease in amniotic fluid index is a long-term effect of chronic fetal hypoxia. Changes in fetal heart rate are the first reaction to hypoxia regardless of etiology [5,9] . A transplacentally administered dexamethasone dose of 12 mg/12 h did not cause changes in BFHR [11] .…”

“…after transplacental glucocorticosteroid administration. Fetal breathing movements were restituted about 4 days after transplacental steroid treatment [4,5] . Betamethasone causes profound but transient suppression of fetal heart rate parameters, which can mimic fetal distress.…”