Changes in peripheral blood neutrophil chemiluminescence during pregnancy

Abstract

We evaluated luminol-dependent chemiluminescence (CL) of maternal peripheral blood neutrophil to clarify the changes of the bactericidal activity in the 92 normal pregnant courses. Neutrophil CL during pregnancy revealed a positive correlation (R2=0.995) between the peak value and the integral value of factors evaluated. Between the first trimester and 34 weeks of pregnancy, CL decreased slightly with course of pregnancy. Then CL decreased significantly during the third trimester, especially one week prior to delivery. On CL study before delivery, the value of neutrophils opsonized with autoserum was lower than that of neutrophils opsonized with pooled serum. Concerning changes in complement 3 (C3), 50 % hemolytic unit of complement (CHSO), immunoglobulin G (IgG) and estradiol during the third trimester, the CHSO value decreased and the estradiol value increased with course of pregnancy. CHSO positively correlated with CL. Estradiol negatively correlated with CL. Therefore, a gradual decrease in neutrophil CL during pregnancy may reflect changes in neutrophil function related to the immune or hormonal kinetics required to continue the pregnancy. However, a transient marked decrease in neutrophil CL during the third trimester may induce susceptibility to infection before delivery, and the subsequent additional increase in CL suggests recovery of the infection-protecting function during delivery. This phenomenon may be a factor predicting the onset of labor pains. [Adv Obstet Gynecol 49 (6); 623-662288, , 1997 (H9.11)]Key word: chemiluminescence, neutrophil, labor pains