Quantitative NBT reduction test with or without stimulation of peripheral polymorphonuclear cells from pregnant women

We performed the nitroblue tetrazolium (NBT) reduction test to investigate the function of polymorphonuclear cells (PMN) from prenatal, intrapartal, postpartal and nonpregnant women with or without stimulation by phorbol myristate acetate (PMN). The capacity for NBT reduction of PMN was significantly increased in pregnancy, followed by a further increases during labor without any stimulation. On the other hand, when stimulated with PMA, there were no differences between pregnancy and labor in the reactivities of PMNs, although they were still significantly higher than those of nonpregnant women. Kallikrein increased the activity of PMN in an in vitro study, suggesting that it may be associated with the change in PMN function in labor.