Maternal blood viscosity and perinatal outcome in steady-state homozygous sickle cell disease.

Homozygous sickle cell disease (HbSS) is a complicating factor in pregnancy resulting in perinatal morbidity and mortality. One of the hallmarks of sickle cell disease is increased whole blood viscosity. The present study was designed to investigate the effect of the maternal blood viscosity on perinatal outcome in steady-state homozygous sickle disease in 19 women admitted to the labor ward of the University Hospital of the West Indies, Mona. Whole blood viscosity was measured with the Wells-Brookfield viscometer at 370C at low (23 sec-1) and high (230 sec-1) shear rates. Measurements were done at native hematocrit. Perinatal outcome was classified as adverse if there was one or more of the following: admission to nursery, birth weight less than 2.5 kg, 5 minute Apgar score less than 7, caesarean section for fetal distress, perinatal death or death before discharge from nursery. The whole blood viscosity value (mean ± SD) at low shear rate was 2.04 ± 0.55 mPa.s and 2.96 ± 0.80 mPa.s at high shear rate. The hematocrit was 25.13 ± 4.18%. The perinatal outcome was good in 10 (53%) subjects and adverse in 9 (47%) subjects. There was no statistically significant difference in the incidence of adverse perinatal outcome between women with low and high blood viscosities in either the low or high shear rates. Similarly, low or high hematocrit did not significantly affect the incidence of adverse perinatal outcome. This could be attributed to their similarity in the whole blood viscosity and hematocrit values.