Umbilical ArteriesFetal Growth RetardationUltrasonography, DopplerInfant, Small for Gestational AgeUltrasonography, PrenatalPregnancySingle Umbilical ArteryUmbilical VeinsInfant, NewbornPlacental CirculationArteriesHeart Rate, FetalBlood Flow VelocityGestational AgeUltrasonography, Doppler, PulsedUmbilical CordFetal DistressPulsatile FlowFetal MonitoringPlacental InsufficiencyFetusCerebral ArteriesFetal DiseasesUltrasonography, Doppler, ColorPulmonary ArteryPregnancy OutcomeFetal BloodPregnancy Trimester, ThirdMiddle Cerebral ArteryCarotid ArteriesPlacentaFemoral ArteryUterine ArteryRenal ArteryPregnancy Trimester, SecondFetal HypoxiaHernia, UmbilicalMesenteric ArteriesFetofetal TransfusionFetal HeartBasilar ArteryHallermann's SyndromePre-EclampsiaEndothelium, VascularPregnancy, High-RiskDigestive System AbnormalitiesApgar ScoreFetal DeathIliac ArteryRegional Blood FlowProspective StudiesVertebral ArteryCoronary Artery BypassPregnancy Trimester, FirstPlacenta Diseases