The distribution of major lymphocyte subsets in cord blood is associated with its pH

Objectives: To assess in venous cord blood the distribution of major lympho cyte subsets according to pH and medications used during labor. Design and methods: Venous cord blood was sampled immediately after labor f rom 70 newborns (35 males and 35 females) delivered vaginally. Lymphocytes were immunophenotyped by Row cytometry and pH was measured using the AVL 90 0 automated blood gas analysis system. Data on birth weight, gestational ag e at delivery, length of labor, presence of stained amniotic fluid, medicat ions used during labor, maternal risk factors, age and parity were collecte d. Results: The percentage of T lymphocytes decreased while the percentage of NK lymphocytes increased with decreasing pH over the whole range of pH valu es. The proportions of T and NK lymphocytes were associated with the admini stration of neuroplegics, spasmolytics or dihydroergotoxin in the first sta ge of labor. Conclusions: Cord blood pH and labor-associated variables should be taken i nto account to adequately interpret the profile of major lymphocyte subsets as a marker of the effect of different prenatal factors on the immune syst em of neonates. (C) 2001 The Canadian Society of Clinical Chemists. All rig hts reserved.