Sample sizes and the outcome criteria used to assess growth up to birth. Nevertheless, our data lead to conclusions consistent with the findings of studies which report significant differences in birth weights between HIVinfected infants, and HIV-exposed EX 527 HDAC inhibitor uninfected infants and/or HIV-exposed uninfected and HIV-unexposed uninfected infants. Nevertheless, some studies found no difference in birth weight between these groups of infants. We observed that HIV-infected infants were smaller at birth than HIV-exposed uninfected infants. This suggests a direct Reversine effect of maternal HIV on fetal growth but the mechanisms of any such effect are unclear. Most vertical HIV transmission occurs late during pregnancy and advanced maternal HIV infection has been reported to be a risk factor for mother–to-child transmission. It is therefore possible that any difference in size at birth between HIV-infected and HIV-exposed uninfected infants may be the consequence of effects of the virus on the mother rather than directly on the fetus. Ryder et al. reported that the mean birth weight of infants whose mothers were at an advanced stage was significantly lower than that of infants born to HIV-infected asymptomatic mothers. Moye et al. showed that in the USA, the mean birth weight Z-scores of HIV-infected infants was lower than those of HIVexposed uninfected children; however, they also reported that disease stage as measured by mean prenatal CD4 T lymphocyte count did not appear to influence birth weight Z-score for HIVexposed, and either HIV-infected or uninfected, infants. HIV staging data were not available in our study, so we are not able to verify this observation. Other authors suggest that the type of ART taken by mothers during pregnancy either for PMTCT or for their own health may explain this relation. However, such drugs are used only as second line regimen, and are therefore not widely taken in Cameroon now. We found a significant difference in birth weight Z-scores between HIV-exposed uninfected and HIV-unexposed uninfected infants. This result confirms the findings from other studies describing lower anthropometric outcomes among HIV-exposed uninfected than HIV-unexposed uninfected infants. By contrast, other authors found that growth measures for the two groups were similar. The difference observed may be linked to maternal HIV and/or related illnesses or to differences in the distributions of other risk factors between the two infant groups. There are various 
possible explanations for this difference. First, studies of in utero exposure to antiretroviral therapy describe inconsistent results. Studies in Cote d’Ivoire, Ireland and Botswana found that triple therapy during pregnancy was associated with low birth weight or with other particular perinatal outcomes, whereas studies in France and Italy did not find any relationship between ART and birth weight. We did not find any association between the use of any ART during pregnancy by mothers of HIV-exposed uninfected infants with SGAG. Second, exposure of the fetus to maternal HIV and related illnesses and/or to ART may lead to immune system abnormalities ; the cause of any such immune abnormality is unclear. Possibly, there is an unusually strong maternal placental response in HIV-infected and ART-treated pregnant women, including substantial placental.