MYELOPEROXIDASE ACTIVITY AND NUCLEAR SEGMENTATION OF MATERNAL NEUTROPHILS DURING NORMAL-PREGNANCY

Myeloperoxidase (MPO) activity and nuclear segmentation of neutrophils were measured in peripheral blood samples from 90 normal pregnant women, arranged in nine groups of ten each, every four weeks at 8-40 weeks gestation and from 25 non-pregnant healthy female controls. A blood autoanalyser (Technicon H*1)was used to determine the mean peroxidase index (MPXI) and the lobularity index (LI) of circulating neutrophils. Mean MPXI levels in pregnancy decreased with gestation to a minimum at 20 weeks' gestation and increased thereafter to reach non-pregnant levels at 36 weeks. Mean LI Values did not change significantly with gestation, but were significantly lower throughout pregnancy compared to controls. There was no significant association between MPXI and LI. It could be postulated that the fall in MPXI during mid-gestation is due to degranulation of neutrophils and the subsequent rise at the end of pregnancy could be a consequence of enhanced MPO activity under the influence of oestrogens. Low LI suggests the production of immature neutrophils during pregnancy.