The Variations of the Sodium Space and the Total Exchangeable Sodium During Pregnancy1

Abstract

Ten normal pregnant women were followed from the 1st trimester of pregnancy through the puerperium with monthly detns. of the Na space and total exchangeable Na (T.E.S.), using the radio-isotope Na24. The Na space was found to have an avg. value of 24.4 (19.3-29.5)% body wt. and the T.E.S. an avg. value of 39.3 (31.9-49.5) m.eq./kg. There was an absolute but not a relative increase in Na space and T.E.S. with progression of pregnancy. No evidence was obtained for the retention of Na in normal pregnancy beyond that accounted for in the products of gestation and the expanded maternal blood vol.