The inorganic phosphorus and calcium in maternal and foetal blood

This study included examinations of the blood of pregnant women in the latter months of pregnancy, of the cord blood of infants, and of mothers' blood within forty-eight hours after labor. The calcium was determined on serum by the Lyman method, and the inorganic phosphorus on the whole blood, using the Bell and Doisy method, without the addition of oxalate or other anticoagulant. The calcium determinations did not indicate significant variations from the normal; the eleven specimens taken antepartem gave an average of 10.4 mg. per cent., whereas eighteen taken postpartem averaged 9.75 mg. per cent. It is possible that tests taken at various periods of pregnancy would give more significant figures. The calcium of the cord blood in eighteen cases gave an average of 10.75 mg. per cent. Howland and Marriott 1 found a normal percentage of calcium in three tests of cord blood. Jones and Nye 2 have reported a calcium content averaging 12.6 mg. per cent. in the plasma of five babies under the age of 14 hours.

As far as we know there have been no tests for phosphorus in the cord blood of infants. McKellips, De Young and Bloor 3 tested the blood of infants during the first 26 days of life and found the inorganic phosphorus the same in the plasma of infants and of adults, and that in the corpuscles somewhat lower in infants. The average inorganic phosphorus of twenty-one cases we found to be 3.71 mg. per cent.; the mothers' blood in these cases averaged 2.89 mg. when taken a day or two following labor. In twelve cases where the inorganic phosphorus was tested during pregnancy, the percentage was 2.77 mg. There are two comments suggested by these figures.