The Variations in Serum Calcium, Protein, and Inorganic Phosphorus in Early and Late Pregnancy, during Parturition and the Puerperium, and in Non-pregnant Women.

Marriott and Howland (1), in 1916, showed that in the blood of uremic patients the serum calcium is low but that there is an increased concentration of inorganic phosphorus. That there might be some relation between the rise of phosphate and the fall of calcium was first suggested by Binger (2), who injected solutions of 0-phosphates intravenously into dogs and observed an elevation of inorganic phosphorus in the blood accompanied by a reduction of serum calcium, an observation later confirmed by Tisdall (3). Salvesen and Linder (4) noted a parallelism between changes of protein and calcium in sera and transudates from patients with nephritis and heart disease. Among uremic patients with low serum calcium and protein, these observers also noted an enormous retention of phosphates, the decrease in calcium being proportional to the increase in phosphorus. Peters and Eiserson (5), working mainly on patients with cardiac and renal disease, evaluated statistically their observations and those of Salvesen and Linder (4) and developed a mathematical equation to express the relationship between serum calcium, inorganic phosphorus, and protein, as follows: