EclampsiaPlacentaOxygenMagnesium SulfatePre-EclampsiaPregnancyMaternal MortalityHELLP SyndromePlacenta DiseasesOxygen ConsumptionPlacenta PreviaPlacenta AccretaPuerperal DisordersHypertension, Pregnancy-InducedReactive Oxygen SpeciesPlacenta, RetainedPregnancy Complications, CardiovascularTrophoblastsAbruptio PlacentaePregnancy OutcomePosterior Leukoencephalopathy SyndromeObstetric Labor ComplicationsTocolytic AgentsPregnancy Complications