Changes in the mean corpuscular red cell volume in women with beta-thalassaemia trait during pregnancy.

Thirty-eight women with beta-thalassaemia trait and thirty-five normal Asian women were studied retrospectively during normal pregnancies. The red cell size increased in both groups, with a mean increase of 2.3 fl (SD 2.3) in the women with beta-thalassaemia trait and a significantly higher increase of 4.3 fl (SD 2.1) in the normal Asian women. The rise in red cell size during pregnancy which is a physiological change, is thus impaired by defective globin-chain synthesis as well as by iron deficiency.