Placental CirculationPlacental Function TestsUmbilical ArteriesPlacentaBlood TransfusionPregnancyErythrocyte TransfusionPlatelet TransfusionExchange Transfusion, Whole BloodBlood Transfusion, AutologousBlood Component TransfusionBlood Transfusion, IntrauterineFetofetal TransfusionBlood CirculationBlood Loss, SurgicalBlood Grouping and CrossmatchingExtracorporeal CirculationLeukocyte TransfusionBlood BanksBlood DonorsPulmonary CirculationBlood PreservationBlood Group IncompatibilityAnemiaAnemia, NeonatalHemoglobinsErythroblastosis, FetalPlateletpheresisPostoperative HemorrhageOperative Blood SalvageIsoantibodiesCollateral CirculationBlood SubstitutesFetomaternal TransfusionTreatment OutcomeAntifibrinolytic AgentsTranexamic Acid