Short-Term (0–48 h) Effects of Maternal Betamethasone Administration on Fetal Heart Rate and Its Variability

Abstract

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...

Maternal cortisol during pregnancy is related to infant cardiac vagal control

“…Greater exposure to maternal cortisol during gestation may reduce infant ability to develop the physiological reserve capacity that is needed to regulate responses to physical and social environments; and this reduced capacity may help to explain the association between lower basal CVC and reduced socio-emotional competence (Liew et al, 2011) and effortful control of attention (Taylor et al, 2015) in children with elevated cortisol exposure. These results are also consistent with previous reports of an inverse association between exposure to synthetic glucocorticoids in utero and fetal basal CVC (Lunshof et al, 2005;Schneider et al, 2010;Senat et al, 1998). Our findings suggest that the effects of exogenous glucocorticoids on fetal CVC are similar to the effects of endogenous maternal cortisol on infant CVC.…”

“…Fetal CVC was reduced following the administration of betamethasone delivered during the third trimester to 8 pregnant mothers at risk of preterm labor (Schneider et al, 2010). Further, shortterm variability in fetal HR increased transiently after the administration of betamethasone followed by a significant reduction that spanned 2-7 days (Lunshof et al, 2005;Senat et al, 1998). In addition, cortical thinning was observed in children between 6 and 10 years of age who were exposed to synthetic glucocorticoids during fetal development (Davis et al, 2013).…”

Comparison of effects of nifedipine and ritodrine on maternal and fetal blood flow patterns in preterm labor

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The Influence of Corticosteroids on Fetal Heart Rate Variability

“…However, this effect was relatively small, with a 3% to 5% decrease in mfHR. 21,27 On days 2 and 3, a trend was seen toward an increase in mfHR in multiple studies. 20,24,27 This trend was significant only in fetuses younger than 27.5 weeks' GA. 25 Other studies showed no effect on mfHR after corticosteroid administration during the study period.…”