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 wom en, arranged in nine groups of ten each, every four weeks at 8-40 week s gestation and from 25 non-pregnant healthy female controls. A blood autoanalyser (Technicon H1)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 a t 20 weeks' gestation and increased thereafter to reach non-pregnant l evels at 36 weeks. Mean LI Values did not change significantly with ge station, but were significantly lower throughout pregnancy compared to controls. There was no significant association between MPXI and LI. I t could be postulated that the fall in MPXI during mid-gestation is du e to degranulation of neutrophils and the subsequent rise at the end o f pregnancy could be a consequence of enhanced MPO activity under the influence of oestrogens. Low LI suggests the production of immature ne utrophils during pregnancy.