Effects of maternal dexamethasone administration on fetal Doppler flow velocity waveforms

Abstract

Objective To investigate the effects of maternal dexamethasone administration on umbilical and fetal Design Cross-sectional study.Setting Department of Obstetrics and Gynaecology, Robert Ballanger Hospital, Aulnay-sous-Bois, Sample Twenty-six pregnant women with singleton pregnancies considered at risk for preterm delivery.At baseline, all pregnancies had normal fetoplacental vascular resistance.Methods These women were given weekly six intravenous doses of 4 mg of dexamethasone eight hours apart.Main outcome measures Doppler studies were performed from both umbilical artery (UA) and fetal middle cerebral artery (MCA) before (day 0), during (day 2), immediately after (day 4) and shortly after (day 7) every steroid course.Results No significant variation was noted in both umbilical artery pulsatility index (PI) and fetal heart rate through dexamethasone therapy. Compared with mean initial values, we found on day 4 a significant decrease in MCA PI of 0.28 (F = 7.17, P c 0.001) and a significant increase in UA:MCA PI ratio of 0.08 (F = 3.85, P = 0.013); in contrast no significant change was documented on days 2 and 7 in both MCA pulsatility index and UA:MCA PI ratio. After multiple regression analysis, only the decrease in fetal middle cerebral artery pulsatility index on day 4 remained significant Conclusions The current study finds in healthy fetuses a transient, significant and unexplained decrease in fetal middle cerebral artery impedance on the fourth day following maternal dexamethasone administration. Further basic research and clinical studies including larger sample sizes or pregnancerebral artery flow velocity waveforms.France.(F=5.84, P = 0.001).cies with fetoplacental dysfunction are needed. that betamethasone and dexamethasone were associated with an increase in long term and short term variability and decreased fetal movements on the first day after steroid administration followed by a decline in fetal heart rate variability on the second day. Similarly, the trial of Mulder et aL6 reported a transient decrease in fetal heart rate variability and in fetal body and breathing movements after betamethasone; conversely, a rise in fetal heart rate variability was noted on the first day after dexamethasone. These effects are more obvious with betamethasone than dexamethas~ne~,~.'~. Evaluation of fetal wellbeing with Doppler waveform studies after maternal corticosteroid administration is therefore important. Knowledge of fetal haemodynamic effects of exogenous corticosteroids is limited. Little is known about the impact of antenatal 0 RCOG 2000 British Journal of Obstetrics and Gynaecology INTRODUCTION

Doppler Measurements in Fetoplacental Vessels after Maternal Betamethasone Administration

“…This effect was attributed to the action of dopamine on the dopaminergic receptors of the vessels and glucocorticoids modifying this reaction [21]. Several in vivo studies of the human fetus did not report a similar reaction of the UA after betamethasone [6,[22][23][24]. However, in these studies, no measurement was performed 30 min after betamethasone administration.…”

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

“…It had mild effect on the fetal heart rate (24). Although in some investigations, it was found that it did not affect Doppler parameters of UA, UtA, and MCA, in some, a decrease in Doppler indices of UA and MCA (25,26) and ductus venosus, particularly PI of MCA, was seen (27). Therefore, it is thought that variations in fetal and fetomaternal circulation in the late period (24-48 hours) of nifedipine and ritodrine in different studies are caused by a combined effect of tocolysis and betamethasone.…”

Corticosteroids and fetal vasculature: effects of hydrocortisone, dexamethasone and betamethasone on human umbilical artery

“…Wallace and Baker 12 have reported that betamethasone administered during pregnancy is associated with decreased placental vascular resistance as measured by return of end-diastolic flow using Doppler ultrasonography in the umbilical artery in pregnancies complicated by absent end-diastolic flow. Similarly, after maternal dexamethasone or betamethasone treatment, a significant decrease in fetal middle cerebral artery impedance (pulsatility index) has been demonstrated in third trimester healthy fetuses 13 and in third trimester high risk pregnancies 14 . No clear explanation exists for this decreased vascular resistance but theories have focussed on the possibility that exogenous corticosteroids increase placental secretion of corticotrophin releasing hormone (CRH), which is a potent vasodilator in the fetal placental circulation 12,14,15 .…”