Pregnancy shows a positive impact on HIV disease progression

2 October 2007. Related: Pregnancy.

Polly Clayden, HIV i-Base

Studies conducted in HIV-positive women receiving either no ART or AZT prophylaxis (HAART) showed that pregnancy either slightly increased the risk of HIV disease progression or had no effect.

A paper authored by Tai and coworkers from Vandebilt University School of Medicine and Comprehensive Care Centre, Nashville, Tennessee, reported findings from an observational cohort study to evaluate disease progression in pregnant women receiving care between 1 January 1997 and 31 December 2004.

In this study HIV disease progression was defined as an AIDS defining illness or death. The investigators found that 759 women met the inclusion criteria; 139 (18%) had at least one pregnancy during follow-up.

There were 174 pregnancies during the study period; 30 women had two pregnancies and five women had three pregnancies. Altogether there were 124 live births, nine spontaneous abortions, three elective abortions, two stillbirths, and one ectopic pregnancy.

In this analysis pregnant women were younger (25, IQR 23-31 years vs. 36, IQR 30-42 years), had higher median baseline CD4 counts (450, IQR 312-660 cells/mm3 vs. 352, IQR 177-560 cells/mm3) and had lower median baseline viral load (3.9, IQR 3.1-4.6 log10 copies/mL vs. 4.2, IQR 3.2-4.9 log10 copies/mL).

119 pregnant and 421 nonpregnant women received HAART and 20 pregnant and 55 nonpregnant women received non- HAART ART only (defined as dual or mono therapy). All pregnant women received ART. Pregnant women were more likely than nonpregnant women to receive HAART. Treatment duration was comparable for pregnant and nonpregnant women.

Pregnant women were more likely to achieve durable virologic suppression (defined as <400 copies/mL) and longer duration of follow-up.

Pregnant women were less likely to have intravenous drug use as a risk factor for HIV acquisition.

The investigators found 11(8%) pregnant and 149 (24%) nonpregnant women either progressed to AIDS or died. The AIDS defining illnesses in pregnant women were Candida oesophagitis, cytomegalovirus retinitis, disseminated cryptococcosis, lymphoma, wasting syndrome, Pneumocystis jirovecii pneumonia and recurrent bacterial pneumonia. In multivariate analysis, after adjusting for baseline CD4 count, and viral load, age, and durable virologic suppression, pregnancy was associated with a decreased risk of disease progression (HR, 0.40 [95%CI, 0.21–0.76); p=0.005).

In a multivariate analysis that included the propensity score for pregnancy in addition to other significant predictors, the risk of disease progression was again significantly lower in pregnant women than in nonpregnant women (HR, 0.40 [95% CI, 0.20–0.79]; p=0.009).

The investigators performed an analysis of 81 matched pregnant and nonpregnant pairs according to age, baseline CD4 count, receipt of HAART, and date of cohort entry. Pregnant women had a lower risk of disease progression both before (HR, 0.10 [95% CI, 0.01-0.89], p=0.04), and after (HR, 0.44 [95%CI, 0.19-1.00], p=0.05) pregnancy.

The investigators wrote: “Our data suggest that, in a setting with high rates of HAART use, pregnancy is independently associated with a decreased risk of HIV disease progression. Further investigation into the responsible underlying biological mechanisms is warranted, particularly the interaction between ART and the immunological changes that occur during pregnancy.”

In an accompanying editorial commentary Kathryn Anastos added: “…women can now have greater confidence that, in addition to protecting their children from MTCT with HAART, their own health will not be compromised by pregnancy, which would place their children at long term risk. For all women pregnancy is something of a gamble: there is no guarantee of a normal pregnancy or a healthy baby. For HIV-infected women becoming pregnant, the findings of Tai et al suggest that, at least for disease progression, the odds may be in their favour.”

Reference:

Tai JH, Mercy A. Udoji MA, Barkanic G et al. Pregnancy and HIV disease progression during the era of Highly Active Antiretroviral Therapy. Journal of Infectious diseases 2007:196. 1044-1052.