{"text_format":"3","workbook":"xlsx","n_sheets":1,"sheets":["Appendix S3"],"not_rendered":{"defined_names":2},"read":"whole","date_system":"1900"}

{"sheet":"Appendix S3","index":0,"n_rows":43,"n_cols":28,"rows_kept":43}
["Author","Year","Title","Study design","Population","Final year of data collection","Country","Country income level","Sample size extracted (eligible population)","Dopler Assessment","Mean maternal age of study population","AEDF cases","REDF cases","CS Rate (%)","Number of stillbirths","Number of early neonatal deaths","Number of perinatal deaths","Number of neonatal deaths","Newcastle-Ottawa Scale (Case Control Studies) ","Newcastle-Ottawa Scale (Cohort Studies) ","Newcastle-Ottawa Scale (Cross-Sectional Studies) ","Random sequence allocation","Allocation concealment","Blinding participants and personnel","Blinding of outcome assessment","Incomplete outcome reporting","Selective outcome reporting","Other bias"]
["Acharaya",2005,"Doppler-derived umbilical artery absolute velocities and their relationship to fetoplacental volume blood flow: a longitudinal study","Cohort study","low-risk women only","Not specified","Norway","High income",130,"Doppler ultrasound of umbilical artery, Doppler ultrasound of umbilical vein",{"v":30,"d":"30.00"},{"v":0,"d":"0.00"},"not specified",18.461538461538463,1,"not specified","not specified","not specified","Not a case-control study",8,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Adali",2009,"Increased visfatin and leptin in pregnancies complicated by pre-eclampsia","Cross-sectional study","low-risk women only",2008,"Turkey","Upper middle income",22,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery",27.55,{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",4,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Adali",2012,"Metastin levels in pregnancies complicated by pre-eclampsia and their relation with disease severity","Cross-sectional study","low-risk women only","Not specified","Turkey","Upper middle income",50,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery",28.34,{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",7,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Aksoy",2015,"Effects of altitude changes on Doppler flow parameters for uterine, umbilical, and mid-cerebral arteries in term pregnancy: A pilot study","Cross-sectional study","low-risk women only",2014,"Turkey","Upper middle income",80,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries)",29.26,{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",7,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Alptekin",2017,"A prospective comparative study to assess the effect of maternal smoking at 37 weeks on Doppler flow velocity waveforms as well as foetal birth weight and placental weight","Case-control study","low-risk women only",2014,"Turkey","Upper middle income",89,"Doppler ultrasound of umbilical artery",{"v":28.2,"d":"28.20"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","not specified",6,"Not a cohort study","Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Arstrom",1989,"Fetal Blood Velocity Waveforms in Normal Pregnancies: A Longitudinal Study","Cohort study","low-risk women only","Not specified","Sweden","High income",22,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries), Doppler ultrasound of fetal aorta","not specified",{"v":0,"d":"0.00"},"not specified",0,0,0,0,"not specified","Not a case-control study",8,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Atkinson",1994,"The Predictive Value of Umbilical Artery Doppler Studies for Preeclampsia or Fetal Growth Retardation in a Preeclampsia Prevention Trial","Individual randomized controlled trial","low-risk women only",1991,"USA","High income",565,"Doppler ultrasound of umbilical artery",{"v":19.9,"d":"19.90"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study","Not a cross-sectional study","low","low","low","low","low","low","unclear"]
["Ayoola",2016,"Normogram of umbilical artery Doppler indices in singleton pregnancies in south-western Nigerian women","Cross-sectional study","low-risk women only",2011,"Nigeria","Low middle income",400,"Doppler ultrasound of umbilical artery",{"v":29.3,"d":"29.30"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",5,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Beattie",1989,"Antenatal screening for intrauterine growth retardation with umbilical artery Doppler ultrasonography","Cohort study","Unselected women only",1987,"Ireland","High income",2097,"Doppler ultrasound of umbilical artery",{"v":26.3,"d":"26.30"},{"v":6,"d":"6.00"},"not specified",12.207916070577014,6,"not specified",13,7,"Not a case-control study",9,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Benzer",2015,"Predictive value of second and third trimester fetal renal artery Doppler indices in idiopathic oligohydramnios and polyhydramnios in low-risk pregnancies: A longitudinal study","Cohort study","low-risk women only","Not specified","Turkey","Upper middle income",264,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal renal arteries",{"v":28.4,"d":"28.40"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","not specified","Not a case-control study",7,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Bolz",2013,"Value of Doppler sonography near term: can umbilical and uterine artery indices in low-risk pregnancies predict perinatal outcome ? ","Cross-sectional study","low-risk women only","Not specified","Germany","High income",365,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery",30.24,{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},29.385964912280706,0,"not specified","not specified","not specified","Not a case-control study","Not a cohort study",4,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Bustos",2014,"Curvas normales de índices de pulsatilidad y tiempo medio de desaceleración de arteria umbilical fetal en población chilena","Cross-sectional study","low-risk women only","Not specified","Chile","High income",877,"Doppler ultrasound of umbilical artery","not specified",{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",5,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Da Costa",2005,"Fetal hemodynamics evaluated by Doppler velocimetry in the second half of pregnancy","Cohort study","low-risk women only","Not specified","Brazil","Upper middle income",33,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal renal arteries, Doppler ultrasound of fetal aorta, Doppler ultrasound of fetal brain (e.g. cerebral arteries)","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",7,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Davies",1992,"Randomised controlled trial of Doppler ultrasound screening of placental perfusion during pregnancy","Individual randomized controlled trial","Unselected women only","Not specified","UK","High income",1246,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery",{"v":29.6,"d":"29.60"},{"v":1,"d":"1.00"},"not specified",6.420545746388442,11,5,17,"not specified","Not a case-control study","Not a cohort study","Not a cross-sectional study","unclear","low","high","high","low","unclear","low"]
["Doppler French Study",1997,"A randomised controlled trial of Doppler ultrasound velocimetry of the umbilical artery in low risk pregnancies ","Individual randomized controlled trial","low-risk women only",1990,"France","High income",1950,"Doppler ultrasound of umbilical artery",{"v":27.9,"d":"27.90"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},12.717948717948719,2,"not specified",3,1,"Not a case-control study","Not a cohort study","Not a cross-sectional study","unclear","low","high","high","low","unclear","low"]
["Drukker",2020,"International gestational age-specific centiles for umbilical artery Doppler indices: a longitudinal prospective cohort study of the INTERGROWTH-21st Project","Cohort study","low-risk women only",2015,"Brazil, UK, Kenya","Multiple",431,"Doppler ultrasound of umbilical artery",{"v":28.9,"d":"28.90"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},{"v":36.89095127610209,"d":"37"},0,0,0,0,"Not a case-control study",9,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Fay",1994,"Color Doppler imaging of the uteroplacental circulation in the middle trimester: observations on the development of a low-resistance circulation","Cohort study","low-risk women only","Not specified","Australia","High income",70,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery","not specified ",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",6,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Ferdousi",2013,"Normal value of pulsatility index of umbilical artery in second and third trimester of pregnancy","Cross-sectional study","low-risk women only",2010,"Bangladesh","Low middle income",60,"Doppler ultrasound of umbilical artery","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",4,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Figueira",2016,"Fetal Hemodynamic Parameters in Low Risk Pregnancies: Doppler Velocimetry of Uterine, Umbilical, and Middle Cerebral Artery","Cohort study","low-risk women only",2009,"Brazil","Upper middle income",63,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries)",{"v":27,"d":"27.00"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",8,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Flo",2010,"Relation between uteroplacental and fetoplacental circulations: a longitudinal study","Cohort study","low-risk women only","Not specified","Norway","High income",53,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified",0,0,0,0,"Not a case-control study",7,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Guo",2019,"Prediction of neonatal acidosis using the cerebroplacental ratio at different gestational weeks","Case-control study","low-risk women only",2016,"China","Upper middle income",1018,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries)",{"v":30.8,"d":"30.80"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},36.93516699410609,"not specified","not specified","not specified","not specified",3,"Not a cohort study","Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Helbig",2013,"Does Antenatal Maternal Psychological Distress Affect Placental Circulation in the Third Trimester?","Cohort study","low-risk women only",2009,"Norway","High income",104,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery, Doppler ultrasound of umbilical vein",{"v":31.5,"d":"31.50"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",8,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Hutter",1991,"Continuous wave Doppler velocimetry of uterine and umbilical blood flow in the second and third trimester of pregnancy: Normal values","Cohort study","low-risk women only",1988,"Germany","High income",427,"Doppler ultrasound of umbilical artery","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",8,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Jorge Neto (a)",2016,"Longitudinal assessment of maternal-fetal Doppler parameters and maternal plasma level of matrix metalloproteinases 2 and 9","Cohort study","low-risk women only","Not specified","Brazil","Upper middle income",33,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries)",{"v":23,"d":"23.00"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},27.27272727272727,"not specified","not specified","not specified","not specified","Not a case-control study",7,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Jorge Neto (b)",2016,"Assessment of nitrite oxide and maternal–fetal Doppler parameters during pregnancy","Cohort study","low-risk women only",2010,"Brazil","Upper middle income",33,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries)",22.46,{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",6,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Kehila",2017,"Correlation between umbilical resistance index and fetal growth: Pilot study","Cohort study","low-risk women only",2016,"Tunisia","Low middle income",77,"Doppler ultrasound of umbilical artery",{"v":32,"d":"32.00"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",6,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Kiserud",2006,"Fetal cardiac output, distribution to the placenta and impact of placental compromise","Cross-sectional study","low-risk women only","Not specified","Norway","High income",170,"Doppler ultrasound of umbilical artery, Doppler ultrasound of umbilical vein, fetal ventricles","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",8,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Lobmaier",2012,"Phase-rectified signal averaging as a new method for surveillance of growth restricted fetuses","Case-control study","low-risk women only",2008,"Germany","High income",43,"Doppler ultrasound of umbilical artery, Dopper ultrasound of fetal brain (e.g. cerberal arteries), Doppler ultrasound of umbilical vein, Doppler ultrasound of fetal cardiac (ductus venosus)",{"v":31,"d":"31.00"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified",5,"Not a cohort study","Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Mason",1983,"Randomised comparison of routine versus highly selective use of Doppler ultrasound inlow risk pregnancies","Individual randomized controlled trial","low-risk women only",1990,"UK","High income",863,"Doppler ultrasound of umbilical artery","not specified",{"v":2,"d":"2.00"},{"v":0,"d":"0.00"},2.857142857142857,"not specified","not specified",4,"not specified","Not a case-control study","Not a cohort study","Not a cross-sectional study","low","low","high","high","low","unclear","unclear"]
["Nkosi",2019,"Screening and managing a low-risk pregnant population using continuous-wave Doppler ultrasound in a low-income population: A cohort analytical study","Cohort study","Unselected women only",2017,"South Africa","Upper middle income",2868,"Doppler ultrasound of umbilical artery",{"v":28.6,"d":"28.60"},{"v":38,"d":"38.00"},{"v":0,"d":"0.00"},20.2441906262308,{"$f":"7+2+4+3","v":16},"not specified",{"$f":"O31+R31","v":24},{"$f":"6+2","v":8},"Not a case-control study",6,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Ome‑Kaius",2017,"Effects of Plasmodium falciparum infection on umbilical artery resistance and intrafetal blood flow distribution: a Doppler ultrasound study from Papua New Guinea","Cohort study","low-risk women only",2013,"PNG","Low middle income",361,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries)",{"v":24.3,"d":"24.30"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",9,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Owen",2003,"Is there a relationship between estimated fetal weight and umbilical artery Doppler impedance indices?","Cohort study","low-risk women only","Not specified","UK","High income",274,"Doppler ultrasound of umbilical artery","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study",7,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Raio",2003,"Umbilical Cord Morphologic Characteristics and Umbilical Artery Doppler Parameters in Intrauterine Growth-Restricted Fetuses","Case-control study","Unselected women only",2003,"Switzerland","High income",168,"Doppler ultrasound of umbilical artery, Doppler ultrasound of umbilical vein",{"v":30,"d":"30.00"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},25.595238095238095,0,0,0,0,8,"Not a cohort study","Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Santos",2016,"Effect of maternal exercises on biophysical fetal and maternal parameters: a transversal study","Cross-sectional study","low-risk women only","Not specified","Brazil","Upper middle income",28,"Doppler ultrasound of umbilical artery, Doppler ultrasound of uterine artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries)",{"v":26,"d":"26.00"},{"v":0,"d":"0.00"},"not specified",57.14285714285714,"not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",7,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Skotnicki",2000,"Doppler examinations in the prognosis of birth status of the newborn","Cross-sectional study","Unselected women only","Not specified","Poland","High income",30,"Doppler ultrasound of umbilical artery, Doppler ultrasound of umbilical vein, Doppler ultrasound of fetal brain (e.g. cerebral arteries), renal atery and descending aorta","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",6,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Souka",2012,"Performance of third-trimester ultrasound for prediction of small-for-gestational-age neonates and evaluation of contingency screening policies","Cross-sectional study","low-risk women only",2010,"Greece","High income",2189,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries),",{"v":31.7,"d":"31.70"},{"v":1,"d":"1.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",9,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Tan",2005,"Umbilical artery resistance index in diabetic pregnancies: The associations with fetal outcome and neonatal septal hypertrophic cardiomyopathy","Case-control study","low-risk women only","Not specified","Malaysia","Upper middle income",50,"Doppler ultrasound of umbilical artery, doppler ultrasound of fetal cardiac circulation","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},12,0,0,0,0,6,"Not a cohort study","Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Thuring",2012,"Placental ischemia and changes in umbilical and uteroplacental arterial and venous hemodynamics.","Case-control study","low-risk women only","Not specified","Sweden","High income",14,"Doppler ultrasound of umbilical artery, Doppler ultrasound of umbilical vein, Doppler ultrasound of uterine artery","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},7.142857142857142,"not specified","not specified","not specified","not specified",6,"Not a cohort study","Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Welsh",2012,"Spatiotemporal image correlation-derived volumetric Doppler impedance indices from spherical samples of the placenta: intraobserver reliability and correlation with conventional umbilical artery Doppler indices","Cross-sectional study","low-risk women only","Not specified","Australia","High income",20,"Doppler ultrasound of umbilical artery","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified","Not a case-control study","Not a cohort study",7,"Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Widnes",2018,"Sex differences in umbilical artery Doppler indices: a longitudinal study","Cohort study","low-risk women only","Not specified","Norway","High income",294,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries)","not specified",{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},13.945578231292515,"not specified","not specified","not specified","not specified","Not a case-control study",8,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Yildiz",2011,"Impact of passive smoking on uterine, umbilical, and fetal middle cerebral artery blood fl ows","Case-control study","low-risk women only","Not specified","Finland","High income",23,"Doppler ultrasound of umbilical artery, Doppler ultrasound of fetal brain (e.g. cerebral arteries), Doppler ultrasound of uterine arteries",{"v":26.7,"d":"26.70"},{"v":0,"d":"0.00"},{"v":0,"d":"0.00"},"not specified","not specified","not specified","not specified","not specified",5,"Not a cohort study","Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]
["Yoon",1993,"Is an abnormal doppler umbilical artery waveform ratio a risk factor for poor perinatal outcome in the non-small for gestational age fetus?","Cohort study","Unselected women only",1990,"South Korea","High income",328,"Doppler ultrasound of umbilical artery",{"v":29.7,"d":"29.70"},{"v":7,"d":"7.00"},"not specified",3.728813559322034,10,"not specified",18,8,"Not a case-control study",6,"Not a cross-sectional study","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial","Not a randomised trial"]