Platelets in pregnancy: hyperdestruction in pregnancy.

Platelet count, mean platelet volume, and platelet volume distribution width were measured with the Coulter counter in 2813 blood samples from 2066 women with an uncomplicated pregnancy. There was a significant fall in the platelet count in the last 8 weeks of gestation, and a significant rise in the mean platelet volume in the last 4 weeks. The platelet volume distribution width rose constantly and significantly throughout pregnancy. These findings indicate an increased platelet consumption (hyperdestruction) throughout normal pregnancy. Platelet volume distribution width appears to be the more sensitive measure of macrothrombocytosis in pregnancy.