Bed RestPregnancyHead-Down TiltWeightlessness SimulationPregnancy OutcomePregnancy ComplicationsPregnancy, AnimalWeightlessness CountermeasuresRestGestational AgeCardiovascular DeconditioningPregnancy Trimester, FirstPregnancy, EctopicPregnancy Trimester, ThirdSpace FlightBedsPregnancy Trimester, SecondPregnancy, MultiplePregnancy TrimestersPregnancy Complications, CardiovascularWeightlessnessPregnancy RatePregnancy TestsPregnancy in DiabeticsFetusPlacentaUltrasonography, PrenatalInfant, NewbornPregnancy, TubalOrthostatic IntolerancePregnancy Complications, NeoplasticPregnancy Complications, InfectiousAbortion, SpontaneousPregnancy in AdolescencePregnancy, High-RiskFetal DeathLower Body Negative PressurePregnancy ProteinsMaternal-Fetal ExchangeUterusPre-EclampsiaBirth WeightPregnancy, UnplannedPrenatal Exposure Delayed EffectsPregnancy, ProlongedTime FactorsFetal DevelopmentPregnancy, UnwantedPregnancy Complications, HematologicPregnancy, TwinFetal DiseasesLactationAbortion, InducedPremature BirthFetal Growth RetardationParityObstetric Labor, PrematureEmbryo ImplantationLabor, ObstetricPrenatal CareBed OccupancyAmniotic FluidEmbryonic and Fetal DevelopmentCesarean SectionPregnancy MaintenanceEmbryo TransferPlasma VolumePregnancy, AbdominalPregnancy Complications, ParasiticTwinsSupine PositionExerciseMuscle, SkeletalFertilization in VitroProspective StudiesMuscular AtrophyPrenatal DiagnosisFetal WeightUterine Cervical IncompetenceEarly AmbulationLitter SizeMaternal ExposureMaternal Nutritional Physiological PhenomenaInfant, PrematureTrophoblastsAbortion, ThreatenedHypertension, Pregnancy-InducedHypotension, OrthostaticAbnormalities, Drug-InducedBody WeightInfant, Low Birth WeightPlacental CirculationDeciduaCongenital AbnormalitiesHypovolemiaFetal HeartDelivery, ObstetricPrenatal Nutritional Physiological PhenomenaPlacenta DiseasesCrown-Rump Length