The effect of race on serum ferritin during parturition.

The purpose of this study was to determine whether differences in ferritin levels due to race were large enough to alter interpretation of ferritin test results during pregnancy. Patients were screened for hemoglobinopathies and other diseases known to affect ferritin levels. Maternal blood samples were obtained at delivery and analyzed for hemoglobin, hematocrit, and ferritin. One hundred thirty-four white and 69 black parturients were studied. Race was found to significantly affect serum ferritin levels p less than 0.001). Whereas blacks had a mean hemoglobin level 0.6 g/dl lower than whites, their mean serum ferritin level was 7.6 ng/ml higher (18.97 +/- 13.6 vs 11.41 +/- 9). No differences were found in the number of red blood cells, smoking status, or most other clinical variables. The mean serum ferritin level of anemic black parturients was higher, although not significantly different, than that of white nonanemic parturients (14.2 +/- 9.5 vs 12.1 +/- 9.4 ng/ml). Furthermore, increasing parity significantly decreased serum ferritin in both races (p less than 0.004). This was not due to differences in the interval between pregnancies. The results show conclusively that black parturients have significantly higher ferritin levels than white parturients. Therefore, different norms need to be established for blacks and whites if ferritin is used to screen for anemia during pregnancy.