EclampsiaPlacentaOxygenSyndromeMagnesium SulfatePre-EclampsiaPregnancyMaternal MortalityHELLP SyndromePlacenta DiseasesOxygen ConsumptionPlacenta PreviaPuerperal DisordersPlacenta AccretaHypertension, Pregnancy-InducedReactive Oxygen SpeciesPlacenta, RetainedPregnancy Complications, CardiovascularDown SyndromeTrophoblastsPregnancy OutcomeMetabolic Syndrome XAbruptio PlacentaePosterior Leukoencephalopathy SyndromePregnancy ComplicationsObstetric Labor ComplicationsTocolytic AgentsGestational Age