The effect of pregnancy on survival in women infected with HIV: a systematic review of the literature and meta-analysis

Objective To investigate the effect of pregnancy on disease progression and survival in women infected with HIV by a systematic review of the literature and meta-analysis. Methods Appropriate publications were identified using electronic and hand searching of relevant journals from 1983 to 1996. Studies were included in the review if they were cohort studies, either prospective or retrospective, or case-control studies which investigated disease progression of pregnant women infected with HIV and included a control group of nonpregnant women infected with HIV for comparison. Methodological quality was assessed for each study. Data were extracted for predetermined outcome measures. Sensitivity analyses were performed to explore the association between pregnancy and disease progression for the following study characteristics: clinical setting (developed or developing countries), methodological quality (high or poor) and whether studies had controlled for potential confounding. Results Seven studies, all prospective cohorts, were eligible to be included in the review. The summary odds ratio for the risk of an adverse maternal outcome related to HIV infection and pregnancy were as follows: death 1.8 (85% CI 0.99-3.3); HIV disease progression 1.41 (95% CI 0.85-2.33); progression to an AIDS-defining illness 1.63 (95% CI 1.00-2.67) and fall of CD4 cell count to below 200x10(6)/L 0.73 (95% CI 0.17-3.06). Sensitivity analyses showed that HIV progression in pregnancy was significantly more common in a developing country setting (odds ratio 3.71, 95% CI 1.82-7.75) than in developed countries (odds ratio 0.55, 95% 0.27-1.11) and also significantly more common in high quality studies when compared to low quality ones, odds ratios 3.71 (95% CI 1.82-7.57) and 0.55 (95% CI 0.27-1.11), respectively. However, there appears to be less progression of HIV disease and progression to AIDS when studies attempted to control for confounding by matching or restriction techniques, although this was not statistically significant in either case. Conclusions The findings of this review have implications for women infected with HIV who are pregnant or are considering a pregnancy. There does appear to be an association between adverse maternal outcomes and pregnancy in women infected with HIV, although this association is not strong. The relation may be due to the result of bias including residual confounding. Further large scale observational studies with long term follow up are required before this issue can be fully resolved.