Mice, Inbred C57BLMice, Inbred C3HAnimals, Outbred StrainsSpecies SpecificityPregnancyGestational AgeFetusPregnancy, AnimalUltrasonography, PrenatalPregnancy Trimester, SecondPlacentaPregnancy Trimester, FirstInfant, NewbornPregnancy Trimester, ThirdMaternal-Fetal ExchangeFetal DevelopmentFetal DiseasesEmbryonic and Fetal DevelopmentPregnancy OutcomeBirth WeightInfant, PrematureFetal DeathLitter SizePregnancy ComplicationsLactationFetal WeightPrenatal Exposure Delayed EffectsUterusAmniotic FluidPremature BirthFetal HeartPregnancy, MultipleObstetric Labor, PrematureFetal Growth RetardationLabor, ObstetricMaternal Nutritional Physiological PhenomenaAnimals, NewbornCrown-Rump LengthHeart Rate, FetalTwinsPlacental CirculationBody WeightSwineParityPrenatal DiagnosisFetal BloodPregnancy TrimestersPrenatal Nutritional Physiological PhenomenaCesarean SectionPre-EclampsiaOrgan SizeMaternal ExposureTrophoblastsFetal Organ Maturity