The analyses of our cohort of HIV-infected pregnant women followed-up in a single hospital with a uniform standard of care have shown rates of LBW and PTD of 12.9% and 11.5% respectively, among patients treated with antiretroviral therapy. This is higher than the average rate of LBW (9.1%) and PTD (7.8%) in public hospitals in Rio de Janeiro 20
Our ratios are similar to a previous report in a Brazilian HIV-infected pregnant women cohort 15
where there was a slightly higher prevalence of LBW (14.3%) in comparison with PTD (10.6%). The lower rates of PTD and LBW in Latin American cohorts when compared to those in Europe and the US could be related to a lower prevalence of illicit drug use and to the absence of women who did not received ARV during pregnancy in the studies.
Stratification of our cohort by type and time of initiation of ARV revealed that HAART use prior to conception is associated with 3.6 times increased risk for LBW and a 5 times increased risk for PTD. LBW in this cohort was also associated with hypertension which is a well known risk for this outcome 21
The higher frequency of PTD and LBW among women treated with ARV prior to conception, seen in our cohort, could be related to a more advanced stage of disease. However, inclusion of a present or past history of symptoms did not show a significant statistical association with any adverse outcome.
Stratification of our cohort by time of initiation of ARV and by type of therapy (dual therapy vs. HAART) revealed that HAART use prior to conception was associated with higher rates of LBW and PTD when compared with its exposure after conception. A VL ≥10,000 copies/ml at the time of delivery was found to be an independent risk factor for PTD. A study from one single center in UK 22
fail to show any increased risk for adverse outcomes in women treated with ARV before pregnancy. The low median VL of these patients (49 copies/ml) could explain this discrepancy. In our cohort, a high viral load was only marginally significant as a predictive factor for PTD and it should be carefully interpretated because VL at delivery was missing in 38% of the population studied.
Our study had some limitations such as absence of data regarding ethnicity, socioeconomic status, route of transmission (although more than 95% were due to heterosexual transmission), a detailed differentiation of previous adverse pregnancy outcomes and body mass index (BMI). A low BMI has been shown to increase two to three times the risk for both LBW and PTD 15, 23, 24
. Another limitation was the lack of data regarding the use of alcohol, tobacco and illicit drugs, which were missing for 35%of our cohort, but the prevalence of these behaviors were overall very low and would not have a great influence in our results. Finally, we were unable to evaluate the risk for individual ARV class.
As ARV use prior to conception cannot be stopped in women who are being treated for their own health, it will be important to continue monitoring adverse pregnancy outcomes in this population to assess if additional or different findings from cohorts with different geographies and demographics arise over time. As the number of patients who become pregnant while on ARV is increasing in Brazil and worldwide, detecting risk factors for adverse outcomes early in gestation will clearly be important to improve management for such women.
Use of antiretroviral prior to conception was associated with an increased risk of premature delivery and low birth weight in a cohort of 696 Brazilian HIV-infected pregnant women during the period 1996–2006.
Stratification of our cohort by time of initiation of ARV and by type of therapy (dual therapy vs. HAART) revealed that HAART use prior to conception was associated with higher rates of PTD (AOR: 5.06; 95% CI: 1.5 – 17.0) and LBW (AOR: AOR: 3.6; 95% CI: 1.7–7.7) when compared with its exposure after conception. Hypertension was also an independent risk factor for LBW.
As ARV use prior to conception cannot be stopped in women who are being treated for their own health, it will be important to continue monitoring adverse pregnancy outcomes in this population to assess if additional or different findings from cohorts with different geographies and demographics arise over time. Detection of risk factors for adverse outcomes early in gestation in this population will clearly be important to improve management for such women.