Variations in CD4 counts during pregnancy in women living with HIV

Objective: Our objective was to determine the frequency at which CD4 counts drop below 200 cells/mm(3) during pregnancy in women living with HIV and to identify factors associated with this.Methods: Data from 2005 to 2020 from two prospective Canadian cohorts of pregnant women living with HIV were extracted. As per national guidelines, women received antiretroviral therapy and CD4 counts were monitored once per trimester and at delivery.Results: Among 775 included cases, 72 (9.3%) had CD4 counts <200 cells/mm(3) at the first pregnancy visit. Of the 703 remaining pregnancies with CD4 counts >= 200 cells/mm(3) at the initial visit, 20 (2.8%) were associated with a drop to <200 cells/mm(3). In univariate analysis, factors associated with this drop were coinfection with hepatitis B virus or hepatitis C virus (odds ratio [OR] 4.0, 95% confidence interval [CI] 1.52-10.50), lower first visit CD4 counts (OR 0.165, 95% CI 0.08-0.34), and baseline haemoglobin levels <11 g/dL (OR 2.89, 95% CI 1.04-8.00). In multivariable analysis, only CD4 count at first visit remained independently associated with this drop. A cut-off CD4 count <= 450 cells/mm(3) at the first pregnancy visit had a sensitivity of 100% to detect cases of CD4 drop to <200 cells/mm(3).Conclusion: A drop of CD4 count to <200 cells/mm(3) is uncommon during pregnancy in women living with HIV. Our results suggest that CD4 monitoring only once in pregnancy would be safe in women whose CD4 count is >450 cells/mm(3) at the first pregnancy visit.