***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: We have done a r and omised controlled trial to assess the effect on primary management and outcome of routine doppler ultrasound examinations of the umbilical and uterine arteries during pregnancy . Over 9 months , 2600 women with singleton pregnancies were recruited from a general obstetric population . Of 2475 women who delivered in hospital after 20 weeks ' gestation , 1246 had been allocated at r and om to receive st and ard antenatal care with routine doppler examinations . The first doppler ultrasound was done at 19 - 22 weeks ' gestation , and thereafter examinations were monthly if the pregnancy was considered high risk ( 192 ) or once at 32 weeks if considered low risk ( 1054 ) . The control group of 1229 women received  st and ard , antenatal care without doppler ultrasonography . The study groups did not differ in number of antenatal admissions or cardiotocographs , gestational age at delivery , method of delivery , frequency of deliveries with fetal distress , or need for resuscitation or admission to the neonatal intensive care unit . More perinatal deaths occurred in the doppler group ( 17 vs 7 , relative risk 2.4 , 95 % Cl 1.00 - 5.76 ) , but only 1 of 11 normally formed stillbirths and none of the 4 normally formed neonatal deaths after 24 weeks ' gestation had an abnormal umbilical-artery doppler examination . We did not demonstrate any improvement in neonatal outcome by routine doppler ultrasound screening of a general obstetric population Abstract Despite widespread application of ultrasound imaging and Doppler blood flow studies , the effects of their frequent and repeated use in pregnancy have not been evaluated in controlled trials . From 2834 women with single pregnancies at 16 - 20 weeks gestation , 1415 were selected at r and om to receive ultrasound imaging and continuous-wave Doppler flow studies at 18 , 24 , 28 , 34 , and 38 weeks gestation ( the intensive group ) and 1419 to receive single ultrasound imaging at 18 weeks ( the regular group ) . Outcome data was obtained from 99 % of women who entered the study . The only difference between the two groups was significantly higher intrauterine growth restriction in the intensive group , when expressed both as birthweight 342 : OBJECTIVE Meta- analysis of r and omized trials of  Doppler ultrasonography in high-risk pregnancies has showed reduced mortality rates among normally formed fetuses . This trial addressed the impact on outcome of umbilical artery velocimetry in a nonselected population ( i.e. , as a screening test in low-risk and high-risk pregnancies ) . STUDY DESIGN A r and omized , controlled trial with Doppler ultrasonographic investigation was performed at two gestational age windows : 26 to 30 weeks and 34 to 36 weeks . The 2986 women were r and omly allocated to revealed or concealed groups in which the Doppler results were either made available or not made available to clinicians ; 1056 women were studied at only the first window , 544 at only the second , and 1386 at both . RESULTS There were no significant differences between groups in antenatal admissions to hospital , preterm deliveries , rates of cesarean section , admission to the neonatal unit , and need for assisted ventilation . There was , however , a trend toward fewer stillbirths in the " revealed " group ( three vs eight , odds ratio 0.34 , confidence interval 0.10 to 1.07 ) . CONCLUSIONS The incidence of stillbirths was reduced by more than half in the Doppler-revealed group , but the confidence intervals were wide and these findings could be compatible with chance Summary . A prospect i ve blind study assessed the efficacy of Doppler examination of the umbilical arteries ( pulsatility index ) as a screening procedure for predicting  small‐for‐gestational‐age and low‐weight‐for‐length ( low ponderal index ) infants .  Birthweight below the 2–3rd and 10th centile and ponderal index below the 3rd and 10th ccntiie were chosen as‘cut‐off levels . Of pregnant women from our university hospital population , 400 were examined at 28 and 34 weeks gestation .  The sensitivity of the test was low , ranging from 16·9 to 41·7 % for the different indices . The predictive value of a negative screening test also was unsatisfactory , ranging from 79·6 % to 97·9 % . It is concluded that a single umbilical artery Doppler examination at 28 or 34 weeks does not satisfy the need in obstetrics for a simple and accurate technique to screen for small‐for‐gestational‐age and  low‐weight‐for‐length  infants in an unselected obstetric population Objective To help answer the question : should Doppler ultrasound of the umbilical circulation be made available to all pregnant women as part of their routine antenatal care This paper proposes a new method for planning r and omized clinical trials . This method is especially suited to comparison of a best st and ard or control treatment with an experimental treatment .  Patients are allocated into two groups by a r and om or chance mechanism . Patients in the first group receive st and ard treatment ; those in the second group are asked if they will accept the experimental therapy ; if they decline , they receive the best st and ard treatment . In the analyses of results , all those in the second group , regardless of treatment , are compared with those in the first group . Any loss of statistical efficiency can be overcome by increased numbers . This experimental plan is indeed a r and omized clinical trial and has the advantage that , before providing consent , a patient will know whether an experimental treatment is to be used OBJECTIVE To assess the predictive value of Doppler umbilical artery velocimetry in a low-risk population with normal fetal biometry . STUDY DESIGN Multicenter prospect i ve study in 17 hospitals with prenatal clinics in France . Two thous and sixteen women who , before 28 weeks gestation were defined as at low risk after routine consultation and after ultrasound . Doppler umbilical artery velocimetry was performed between 28 and 34 weeks gestation . Confounding factors were used to perform multivariate regression . RESULTS 1903 cases were analysed and 192 ( 10.1 % ) had an abnormal Doppler Resistance Index ( RI ) . The abnormal Doppler group contained a significantly higher frequency of severe and moderate small for gestational age infants ( SGA ) , both severe and moderate with a sensitivity of 25.5 and 18.8 % respectively . There was no difference in hypertensive disorders or criteria of fetal distress . Mean birth weight was very significantly lower in the abnormal group ( 162 g ) . Birth weight was very significantly linked to RI after taking into account confounding variables in the multiple linear regression model ( continuous relationship ) . After multiple logistic regression , the odds ratio associated with an abnormal Doppler result , adjusted for all the confounding factors , was 2.3 ( 95 % CI 1.5 - 3.7 ) for moderate SGA and 3.5 ( 95 % CI of 1.8 - 7.1 ) for severe SGA . CONCLUSION Low umbilical Doppler RI is predictive with moderate or severe SGA in a low-risk population with normal fetal biometry , even when the information generally available in clinical practice and ultrasound parameters are taken into account . There is a continuous relationship between RI and birthweight . This predictive value can not , however , lead to an improvement in neonatal health unless effective measures to prevent SGA exist and umbilical Doppler should not be used in low-risk population on a routine basis 
    Output:
    
Based on existing evidence , routine Doppler ultrasound examination in low risk or unselected population s 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 .
There is no available evidence to assess maternal outcomes , particularly psychological effects .
REVIEW ER 'S CONCLUSIONS Based on existing evidence , routine Doppler ultrasound in low risk or unselected population s does not confer benefit on mother or baby .