Effects of Dexamethasone on Fetal Doppler Indices

Objective: To assess the impacts of dexamethasone given to the mother on fetal Doppler flow velocity waveforms of both umbilical and fetal middle cerebral arteries in pregnancies with normal fetoplacental vascular resistance. Study Design: Prospective Study. Patients and Methods: Pregnant women between 28 weeks and 34 weeks gestation at risk of preterm labour, Preterm birth was anticipated on the basis of: History of previous preterm birth, dilating cervix, antepartum hemorrhage, Preterm premature rupture of the membranes, increased amniotic fluid volume, Patients with possible need for early termination of pregnancy including those with history of previous uterine rupture and hysterotomy. Intramuscular dexamethasone was given as 4 doses dexamethasone (6mg/12 hours for 48 hrs), Doppler ultrasound assessment of umbilical artery (UA), middle cerebral artery (MCA) both resistive index (RI) and pulsatility index (PI) were done as baseline, day 2 and day 4. Results: There was no significant variation noted in UA or MCA PI or RI throughout dexamethasone therapy. Conclusion: Dexamethasone treatment was not associated with significant changes in the mean values of the pulsatility, resistive indices in umbilical artery and fetal middle cerebral artery, Awareness of this drug-induced effect might prevent unnecessary iatrogenic delivery of preterm fetuses.