Fetal and umbilical Doppler ultrasound in normal pregnancy
Background One of the main aims of routine antenatal care is to identify the 'at risk' fetus in order to apply clinical interventions which could result in reduced perinatal morbidity and mortality. Doppler ultrasound study of umbilical artery waveforms helps to identify the compromised fetus in 'high-risk' pregnancies and, therefore, deserves assessment as a screening test in 'low-risk' pregnancies. Objectives Objectives To assess the effects on obstetric practice and pregnancy outcome of routine fetal and umbilical Doppler ultrasound in unselected and low-risk pregnancies. Search methods Search methods We searched the Cochrane Pregnancy and Childbirth Group Trials Register (May 2010). Selection criteria Selection criteria Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of umbilical and fetal vessels waveforms in unselected pregnancies compared to no Doppler ultrasound. Studies where uterine vessels have been assessed together with fetal and umbilical vessels have been included. Data collection and analysis Data collection and analysis Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Main results Main results We included five trials involving 14,185 women. The methodological quality of the trials was generally unclear because of insufficient data included in the reports.Routine fetal and umbilical Doppler ultrasound examination in low-risk or unselected populations did not result in increased antenatal, obstetric and neonatal interventions, and no overall differences were detected for substantive short term clinical outcomes such as perinatal mortality. There is no available evidence to assess the effect on substantive long term outcomes such as childhood neurodevelopment and no data to assess maternal outcomes, particularly psychological effects. Authors' conclusions Authors' conclusions Existing evidence does not provide conclusive evidence that the use of routine umbilical artery Doppler ultrasound, or combination of umbilical and uterine artery Doppler ultrasound in low-risk or unselected populations benefits either mother or baby. Future studies should be designed to address small changes in perinatal outcome, and should focus on potentially preventable deaths.