Bed RestPregnancyHead-Down TiltWeightlessness SimulationPregnancy OutcomePregnancy ComplicationsWeightlessness CountermeasuresRestPregnancy, AnimalCardiovascular DeconditioningPregnancy, EctopicSpace FlightBedsHypertensionPregnancy Trimester, FirstWeightlessnessPregnancy Complications, CardiovascularPregnancy RatePregnancy Trimester, ThirdPregnancy TrimestersPregnancy TestsPregnancy, MultipleBlood PressureOrthostatic IntolerancePregnancy in DiabeticsPregnancy, TubalPregnancy Trimester, SecondPregnancy Complications, NeoplasticPregnancy in AdolescenceLower Body Negative PressurePregnancy Complications, InfectiousAbortion, SpontaneousGestational AgePregnancy ProteinsRisk FactorsTime FactorsPregnancy, UnplannedPregnancy, High-RiskPregnancy, UnwantedInfant, NewbornPre-EclampsiaPregnancy Complications, HematologicExercisePlacentaBed OccupancyPregnancy, ProlongedPregnancy, TwinPlasma VolumeAntihypertensive AgentsFetal DeathSupine PositionUterusMuscular AtrophyBirth WeightMuscle, SkeletalAbortion, InducedEarly AmbulationPregnancy Complications, ParasiticPregnancy, AbdominalPrevalenceBlood Pressure DeterminationProspective StudiesPregnancy MaintenanceEmbryo ImplantationUltrasonography, PrenatalHypotension, OrthostaticPrenatal Exposure Delayed EffectsEmbryo TransferPrenatal CareFertilization in VitroMaternal-Fetal ExchangeCross-Sectional StudiesHypovolemiaParityCohort StudiesVascular CapacitanceBody WeightUterine Cervical IncompetenceInfant, Low Birth WeightReference ValuesHeart RateAbortion, ThreatenedAmino Acids, EssentialImmobilizationProgesteroneVascular ResistanceRetrospective Studies