الفهرس 
Preterm laborOnly 14 pages are availabe for public view
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Abstract
Abstract
Objective: To evaluate the effects of antenatal maternal Dexamethasone administration on both umbilical and fetal middle cerebral arteries Doppler indices in singleton pregnancies considered at risk for preterm delivery.
Patients and methods
A randomized, controlled trial including one hundred pregnant women considered at risk for preterm delivery. These women received dexamethasone to enhance fetal lung maturation (6 mg of Dexamethasone administered intramuscularly twelve hours apart for 4 doses).Doppler studies were performed for 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) steroid course.
Results
We found on day 4 a significant decrease in MCA PI (F = 3.23, P = 0.02) and a significant increase in UA: MCA PI ratio (F =4.15, P = 0.02); in contrast non-significant change was documented on days 2 and 7 in both MCA pulsatility index and UA: MCA PI ratio. After complete statistical analysis of the collected data, only the decrease in fetal middle cerebral artery pulsatility index on day 4 remained significant.
Conclusions
Administration of dexamethasone improves Doppler indices, biophysical profile and decrease NICU admission.in healthy fetuses a transient, significant and unexplained decrease in fetal middle cerebral artery impedance occur on the fourth day following maternal dexamethasone administration.
Introduction
Preterm birth is an important perinatal health problem across the globe as its rates have been reported to range from 5% to 7% of live births in some developed countries, but are estimated to be substantially higher in developing countries (7).
Preterm birth is a leading cause of perinatal mortality and morbidity and has adverse long-term consequences for the child health (2). Whilst all births before 37 weeks gestation are defined as preterm, the vast majority of morbidity and mortality relates to early delivery before 32 weeks (136).
Respiratory distress syndrome (RDS) is a serious complication of preterm birth and the primary cause of early neonatal mortality and disability. (1) There is strong evidence supporting the use of antenatal corticosteroids in women at risk of preterm birth to promote fetal lung maturation and reduce neonatal mortality and morbidity (3).
Doppler flow velocity waveform analysis of fetal vessels is one of the main methods for evaluating fetus health before labor (137). Doppler velocimetry of utero-placental vessels identifies alterations of placental perfusion and is valuable in the assessment of fetal brain, heart, and liver perfusion (138).