Maternal hemoglobin F levels may have an adverse effect on neonatal birth weight in pregnancies with sickle cell disease.

A total of 26 patients with sickle cell disease were followed up through 32 pregnancies. There was no correlation between days in hospital or number of painful crises and either birth weight or birth weight percentile. The number of dense irreversibly sickled and least deformable cells was negatively correlated with birth weight percentile (r = -0.63, p less than 0.01). Patients' initial hemoglobin levels were positively correlated with birth weight percentile (r = 0.52, p less than 0.004). Hemoglobin F, on the other hand, was significantly inversely correlated with birth weight percentile. Nine pregnancies with small-for-gestational-age infants had an average hemoglobin level of 9.1% +/- 4.5%. In contrast, patients who were delivered of appropriate-for-gestational-age infants (23 pregnancies) had an average hemoglobin F level of 3.6% +/- 2.9% (p less than 0.01). We conclude that total hemoglobin levels and dense cells are correlated with birth weight percentile; moreover, the higher the maternal hemoglobin F levels the higher the risk of small-for-gestational-age infants. We speculate that although high hemoglobin levels may be beneficial to the fetus, high maternal hemoglobin F levels could increase the desaturation of non-F cells and induce placental obstruction.