Serum haptoglobins in pregnancy.

Serum haptoglobin types and levels were determined by starch gel electrophoresis and a colorimetric method based on the peroxidase activity of the haptoglobin-methaemoglobin complex in 220 pregnant women and 120 normal female subjects. The frequency distributions of haptoglobin types in the 2 groups of subjects were similar. No correlation between the number of gravida or duration of pregnancy and serum haptoglobin levels were observed in pregnant subjects. Haptoglobin values were found to be low in 39% of pregnant women and a direct relationship between these low haptoglobin levels and the haemoglobin concentrations was observed. The cause of low haptoglobin values was probably haemodilution and increased blood estrogen concentrations during pregnancy.