Volume and sodium concentration studies in 300 saline-induced abortions

In an attempt to clarify the role of volume changes and Na concentration in saline-induced midtrimester abortions, 800 amniotic fluid samples were studied in 300 cases. The immediate postinfusion values of Na ranged as high as 3,000 mEg. per liter and as low as 1,200 mEg. per liter, still resulting in abortion. In earlier gestation, higher Na concentration and greater volume increase was needed for successful induction of abortion. Volume increase, within limits, compensated for Na concentration decrease. Osmotically induced volume changes were proportionatenate to the advancing stage of gestation.