Peripheral polymorphonuclear leukocyte priming contributes to oxidative stress in early pregnancy.

OBJECTIVE

The cause of elevated blood leukocyte count in pregnancy is unknown. We hypothesized that priming of peripheral polymorphonuclear leukocytes (PMNL) caused this elevation.

METHODS

Eleven women in the first trimester of pregnancy were included in this prospective study. Peripheral venous blood was drawn twice from each woman, before and after a medical abortion (pregnant and nonpregnant, respectively). Complete blood cell count, plasma alkaline phosphatase (ALP), and rate of superoxide release from separated phobrol 12-myristate-13-acetate (PMA)-stimulated PMNL were determined.

RESULTS

The PMNL count in early pregnancy was significantly higher, with a significant increase in the PMNL rate of superoxide release compared to the nonpregnant state. A linear correlation between the rates of superoxide release and PMNL counts before and during pregnancy was found. ALP levels were significantly elevated in early pregnancy.

CONCLUSION

The increased PMNL count is probably a compensatory response to PMNL priming. The increased rate of superoxide release from primed PMNL may contribute to oxidative stress in early pregnancy.