Other consideration:(4)
Fluids and electrolyte changes occur as a result of the increase in interstitial fluid by as much as 6 litres.To maintain this isotonic hyperhydration sodium is retained.
Although total body sodium is increased the serum sodium is 2-3 meq/L below non pregnant level.
The infusion of sodium free fluids such as 5% dextrose in water can lead to hyponatremia in mother and neonate (Lind,1983), potassium levels are also somewhat lower in pregnancy.
Plasma osmolality is reduced by as much as 10 mosm /kg H20(Hytten 78) within the first few weeks of pregnancy due to the fall in electrolyte and urea. Urea falls in early pregnancy to about a quarter...
