Fetal and umbilical Doppler ultrasound in high-risk pregnancies.
BACKGROUND
Abnormal blood flow patterns in fetal circulation detected by Doppler ultrasound may indicate poor fetal prognosis. It is also possible false positive Doppler ultrasound findings could encourage inappropriate early delivery.


OBJECTIVE
The objective of this review was to assess the effects of Doppler ultrasound used to assess fetal well-being in high-risk pregnancies on obstetric care and fetal outcomes.


METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2009) and the reference lists of identified studies.


METHODS
Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of umbilical and fetal vessels waveforms in high-risk pregnancies compared to no Doppler ultrasound.


METHODS
Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Data entry was checked.


RESULTS
Eighteen completed studies involving just over 10,000 women were included. The trials were generally of unclear quality with some evidence of possible publication bias. The use of Doppler ultrasound in high-risk pregnancy was associated a reduction in perinatal deaths (risk ratio (RR) 0.71, 95% confidence interval (CI) 0.52 to 0.98, 16 studies, 10,225 babies, 1.2% versus 1.7 %, numbers needed to treat = 203; 95%CI 103 to 4352). There were also fewer inductions of labour (average RR 0.89, 95% CI 0.80 to 0.99, 10 studies, 5633 women, random effects) and fewer caesarean sections (RR 0.90, 95% CI 0.84 to 0.97, 14 studies, 7918 women). No difference was found in operative vaginal births (RR 0.95, 95% CI 0.80 to 1.14, four studies, 2813 women) nor in Apgar scores less than seven at five minutes (RR 0.92, 95% CI 0.69 to 1.24, seven studies, 6321 babies).


CONCLUSIONS
Current evidence suggests that the use of Doppler ultrasound in high-risk pregnancies reduced the risk of perinatal deaths and resulted in less obstetric interventions. The quality of the current evidence was not of high quality, therefore, the results should be interpreted with some caution. Studies of high quality with follow-up studies on neurological development are needed.
Alfirevic
Zarko
Z
School of Reproductive and Developmental Medicine, Division of Perinatal and Reproductive Medicine, The University of Liverpool, First Floor, Liverpool Women's NHS Foundation Trust, Crown Street, Liverpool, UK, L8 7SS.
Stampalija
Tamara
T
Gyte
Gillian Ml
GM
D002585:Cesarean Section / Q000706:statistics & numerical data; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D006801:Humans; D007751:Labor, Induced / Q000706:statistics & numerical data; D054238:Perinatal Mortality; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D016032:Randomized Controlled Trials as Topic; D016216:Ultrasonography, Prenatal; D014470:Umbilical Cord / Q000098:blood supply / Q000000981:diagnostic imaging*