Recent evidence implicates the immune system and the clotting mechanisms in the pathophysiology of sickle cell disease (SCD). This study investigates the association of steady state platelet count with the severity of SCD in pregnancy. A total of 40 SCD women who were asymptomatic early in pregnancy were studied retrospectively: 14 remained asymptomatic throughout pregnancy and 26 developed at least one SCD-related complication. The early pregnancy platelet count was compared between the two groups using t-test and its ability to predict SCD-related complications in pregnancy was investigated using Receiver-Operator Characteristics (ROC) curve. Compared with asymptomatic patients, women who developed SCD-related complications had significantly higher early-pregnancy platelet count [328x10(9)/l (95% CI: 268-389) vs 210x10(9)/l (146-275), p < 0.01]. The area under the ROC curve was 76.4% (95% CI 59.7-93.2). These indicate that the platelet count in early pregnancy is significantly higher in SCD patients who subsequently develop SCD-related complications and may be used for screening.