ObjectiveTo assess changes in lymphocyte substes during pregnancy and 1 year postpartum in human immunodeficiency virus (HIV)-infected women.MehtodsChanges in CD4+and CD8+cell counts, CD4 and CD8 percents, CD4/CD8 ratio, and total lymphocyte count and percent were assessed in each of 226 HIV-infected women followed during pregnancy and 1 year postpartum, and for each of 100 nonpregnant HIV-infected woman during 1 year. Trends over time were compared between pregnant women with and without several covariates. Postpartum changes over a 1-year period were compared to a 1-year period in the nonpregnant cohort.ResultsThere was a mena increase of 2.76 per week in the CD4+cell count during pregnancy (P= .04). No other characteristics changed significantly during pregnancy. The mean CD4+and CD8+cell counts, the CD8 percent, and the total lymphocyte count and percent increased immediately postdelivery. During the first postpartum year, there were statistically significant declines in the absolute CD4+and CD8+cell counts, the relative CD4 and CD8 percentages, and the total lymphocyte count and percentage. The rate of change for CD4+and CD8+counts, but not for CD4 percent, was less during 1 year in the nonpregnant cohort than in the first postpartum year, and the CD8 percent increased in the nonpregnant women. a wide variability in trends of all measurements during pregnancy was seen.ConclusionDuring pregnancy, CD4 and CD8 percentages remain stable. There are no clinically significant changes during pregnancy or postpartum in any lymphocyte parameter we assessed. Postpartum changes in lymphocytes and lymphocyte subsets most likely represent a return to base-line from the physiologic changes of pregnancy and the immediate postpartum period.