***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 
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    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 The objective of this study was to evaluate and characterise by study of newborn biometry a possible effect on birthweight which we observed previously in a r and omised controlled trial of multiple prenatal ultrasound examinations . A total of 2743 women with single pregnancies had been allocated at r and om to either a protocol of ultrasound imaging and continuous wave Doppler studies at 18 , 24 , 28 , 34 and 38 weeks gestation ( intensive group ) , or to a protocol of a single imaging examination at 18 weeks and further imaging scans only as clinical ly indicated ( regular group ) . When compared with those in the regular group , and adjusted for other confounding variables , normally formed babies of term gestational age in the intensive group tended to be shorter when measured at birth ( P = 0.123 ) and on day 2 - 3 of age ( P = 0.068 ) . There were statistically insignificant reductions in the circumferences of the chest , abdomen and mid-arm ; and in the skinfold thicknesses of the triceps , parascapular and subscapular regions . Principal component analysis showed a trend for a reduction for the skeletal component ( P = 0.085 ) but not for the soft tissue component ( P = 0.332 ) . Comparison of the neonatal biometry in the two groups is not conclusive , but the differential effects on the various growth parameters suggest that if multiple scans do indeed restrict fetal growth , the mechanism is more likely to be an effect on bone growth rather than a reduction in nutrient supply from the placenta 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 To assess the addition value of umbilical artery Doppler ultrasound added to st and ard ultrasound biometry measurements in the management of twin pregnancies 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 Objective To assess the effectiveness of a pre‐eclampsia prevention strategy based on routine uterine artery Doppler flow velocity waveform examination during the second trimester of pregnancy , followed by a prescription for 100 mg aspirin in the case of abnormal Doppler findings OBJECTIVES Through comprehensive ophthalmic examination of adult offspring we sought to determine the impact of multiple prenatal ultrasound scans on ocular development . METHODS 2743 pregnant women recruited to the Western Australian Pregnancy ( Raine ) Cohort study during 1989 - 1991 were r and omized to receive at King Edward Memorial Hospital , Western Australia either multiple prenatal ultrasound scans and Doppler flow studies ( intensive group ) or a single ultrasound scan at 18 weeks ' gestation . Neonatal birth weight of the offspring and other physical measurements were collected prospect ively . At age 20 years , participants underwent a comprehensive ophthalmic examination including measurement of ocular biometry and visual acuity . RESULTS Complete data were available for 1134 adult offspring participants . The mothers of 563 of these had been r and omized to receive multiple prenatal ultrasound scans .  The mean age of participants at follow-up was 20.0 years . There was no statistically significant difference between the two groups with regard to ocular biometric or visual outcomes , except for slightly higher intraocular pressure identified in individuals exposed to multiple ultrasound scans ( P = 0.034 ) . Although infants in the intensive-ultrasound arm were more likely to have birth weights in the lower quartiles , this was not reflected in adult eye development . Axial length , lens thickness , corneal curvature and thickness and optic cup to disc ratio ( a risk factor for glaucomatous optic neuropathy ) were not significantly influenced by the more frequent ultrasound protocol . CONCLUSIONS Prior to this study , there was a paucity of safety data for ultrasound with regard to eye development . We found that frequent in-utero exposure to ultrasound , including B-mode imaging and the use of spectral Doppler mode from 18 weeks ' gestation , had no significant impact on visual outcomes or ocular biometry An existing r and omised controlled trial was used to investigate whether multiple ultrasound scans may be associated with the autism phenotype .  From 2,834 single pregnancies , 1,415 were selected at r and om to receive ultrasound imaging and continuous wave Doppler flow studies at five points throughout pregnancy ( Intensive ) and 1,419 to receive a single imaging scan at 18 weeks ( Regular ) , with further scans only as indicated on clinical grounds . There was no significant difference in the rate of Autism Spectrum Disorder between the Regular ( 9/1,125 , 0.8 % ) and Intensive ( 7/1,167 , 0.6 % ) groups , nor a difference between groups in the level of autistic-like traits in early adulthood . There is no clear link between the frequency and timing of prenatal ultrasound scans and the autism phenotype BACKGROUND Despite the widespread use of prenatal ultrasound studies , there are no published data from r and omised controlled trials describing childhood outcomes that might be influenced by repeated ultrasound exposures . We previously undertook a r and omised controlled trial to assess the effects of multiple studies on pregnancy and childhood outcomes and reported that those pregnancies allocated to receive multiple examinations had an unexplained and significant increase in the proportion of growth restricted newborns . Our aim was to investigate the possible effects of multiple prenatal ultrasound scans on growth and development in childhood . Here , we provide follow-up data of the childrens ' development . METHODS Physical and developmental assessment s were done on children whose pregnant mothers had been allocated at r and om to a protocol of five studies of ultrasound imaging and umbilical artery Doppler flow velocity waveform between 18 and 38 weeks ' gestation ( intensive group n=1490 ) or a single imaging study at 18 weeks ' gestation ( regular group n=1477 ) . We used generalised logistic and linear regression models to assess the group differences in developmental and growth outcomes over time . Primary data analysis was done by intention-to-treat . FINDINGS Examinations were done at 1 , 2 , 3 , 5 , and 8 years of age on children born without congenital abnormalities and from singleton pregnancies ( intensive group n=1362 , regular group n=1352 ) . The follow-up rate at 1 year was 85 % ( 2310/2714 ) and at 8 years was 75 % ( 2042/2714 ) . By 1 year of age and thereafter , physical sizes were similar in the two groups . There were no significant differences indicating deleterious effects of multiple ultrasound studies at any age as measured by st and ard tests of childhood speech , language , behaviour , and neurological development . INTERPRETATION Exposure to multiple prenatal ultrasound examinations from 18 weeks ' gestation onwards might be associated with a small effect on fetal growth but is followed in childhood by growth and measures of developmental outcome similar to those in children who had received a single prenatal scan BACKGROUND Comparing the relative effectiveness of interventions on specific outcomes across trials can be problematic due to differences in the choice and definitions of outcome measures used by research ers . We sought to identify a minimum set of outcome measures for evaluating models of maternity care from the perspective of key stakeholders . METHODS A 3-round , electronic Delphi survey design was used . Setting was multinational , comprising a range of key stakeholders . Participants consisted of a single heterogeneous panel of maternity service users , midwives , obstetricians , pediatricians/neonatologists , family physicians/general practitioners , policy-makers , service practitioners , and research ers of maternity care . Members of the panel self-assessed their expertise in evaluating models of maternity care . RESULTS A total of 320 people from 28 countries expressed willingness to take part in this survey . Round 1 was completed by 218 ( 68.1 % ) participants , of whom 173 ( 79.4 % ) completed round 2 and 152 ( 87.9 % ) of these completed round 3 . Fifty outcomes were identified , with both a mean value greater than the overall group mean for all outcomes combined ( x=4.18 ) and rated 4 or more on a 5-point Likert-type scale for importance of inclusion in a minimum data set of outcome measures by at least 70 percent of respondents . Three outcomes were collapsed into a single outcome so that the final minimum set includes 48 outcomes . CONCLUSIONS Given the inconsistencies in the choice of outcome measures routinely collected and reported in r and omized evaluations of maternity care , it is hoped that use of the data set will increase the potential for national and international comparisons of models for maternity care . Although not intended to be prescriptive or to inhibit the collection of other outcomes , we hope that the core set will make it easier to assess the care of women and their babies during pregnancy and childbirth 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 Objectives To assess whether systematic screening with an uterine artery Doppler in low risk pregnant women followed by the prescription of low dose aspirin in cases with ab 
    Output:
    
Overall , routine fetal and umbilical Doppler ultrasound examination in low-risk or unselected population s did not result in increased antenatal , obstetric and neonatal interventions .
There were no group differences noted for the review 's primary outcomes of perinatal death and neonatal morbidity .
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 population s benefits either mother or baby .