Risk factors for HIV infection among asymptomatic pregnant women attendingan antenatal clinic in western Kenya

Our objective was to evaluate HIV prevalence and identify risk factors for PW infection among women attending the antenatal clinic (ANC) at a large pu blic hospital in Kisumu town, western Kenya. Between June 1996 and November 1997, in the context of a study to determine the effect of placental malar ia on mother-to-child transmission of HN in western Kenya, HIV-1 antibody t esting was offered to women with a singleton uncomplicated pregnancy of gre ater than or equal to 32 weeks' gestation attending the ANC. Women were int erviewed using a structured questionnaire and had a fingerstick blood sampl e collected for haemoglobin (Hb), malaria smears, and HIV antibody testing. Overall HIV seroprevalence was 26.1% (743/2844) (95% confidence interval (C I): 24.5-27.7) and in bivariate evaluation was significantly associated wit h anaemia (Hb <11 g/dl) (risk ratio (RR) 1.8), malarial parasitaemia (RR 1. 6), fever (axillary temperature greater than or equal to 37.5 degrees C at screening) (RR 1.6), a history of being treated for either vaginal discharg e (RR 1.5) or tuberculosis (RR 1.6), reported alcohol consumption (RR 1.6), being an unmarried multigravida (RR 2.2) or a history of the most recent c hild having died (RR 2.0). Poisson regression analysis for all women identi fied 5 significant factors independently associated with HIV seropositivity : anaemia (adjusted RR 1.7; 95% CI 1.3-2.0), malarial parasitaemia (adjuste d RR 1.7; 95% CI 1.4-2.0), a history of being treated for vaginal discharge (adjusted RR 1.5; 95% CI 1.1-2.0), fever (adjusted RR 2.0; 95% CI 1.3-3.2) and reported alcohol consumption (adjusted RR 1.6; 95% CI 1.1-2.5). Multig ravidae women whose most recent child had died were also more Likely to be HIV seropositive (adjusted RR 1.9; 95% CI 1.7-2.8). Only 5.5% (156/2844) of the women had none of these risk factors, of whom 12% (18/156) were HIV(+) . Even though the model containing the 5 identified factors fitted the data well (goodness-of-fit chi(2)=18.41, P=0.10), its collective capacity to pr edict HIV infection was poor; while 74% of the truly positive women were co rrectly predicted positive by the model, 52% of the truly negative women we re misclassified. Among pregnant women attending the ANC in western Kenya, we were unable to identify a subgroup at risk of HIV infection using non-serological informat ion, indicating that wherever possible universal access to voluntary HIV co unselling and testing would be preferable to targeted screening.