Incidence and factors associated with antenatal HIV seroconversion among women at term presenting in Mulago Hospital

Abstract

Introduction: Mother to Child Transmission of HIV (MTCT) is the leading mode of HIV transmission to children. A combination of antiretroviral medicines and practice of various obstetric care procedures like avoidance of artificial rupture of membranes, avoiding instrumental delivery, avoiding vigorous suction of the baby following delivery and others have markedly reduced MTCT of HIV. The Uganda PMTCT guidelines recommend that pregnant women are counseled and tested for HIV as soon as they present to the antenatal clinic and have a repeat test done three months following the initial test. This study was conducted in Mulago Hospital from January 2011 to March 2011 where women at term were counseled and provided with an HIV test. There is evidence that HIV seroconversion occurs during the antenatal period and only having a Repeat HIV test either late in pregnancy or at the time of labour can identify those mothers who have seroconverted against HIV so as to provide them with PMTCT services. Objective: This study was intended to establish the incidence and factors associated with antenatal HIV seroconversion among mothers in labour in Mulago Hospital. Design: Retrospective cohort study. Study site: Upperand Lower Mulago labour wards. Consecutive sampling was used to enroll the participants. A total of 3052 mothers were screened at the admission desk in the labour ward by reviewing their antenatal records and assessing their HIV status in the previous three months or more. Of those screened, 1282who had been tested for HIV and were negative three months or more during antenatal were eligible and enrolled. Data collection and management: An interviewer administered questionnaire was used to gather demographic data and information about factors associated with HIV seroconversion. A rapid HIV test was done to ascertain the HIV sero-status of the participant. Univariate analysis was used for continuous and categorical variables and Chi square used to determine the level of significance of the different factors affecting antenatal HIV seroconversion. Logistic regression was used to control for confounders. Results: 1) Fifteen of the 1282 mothers had seroconverted by the time of the repeat HIV test in labour. Total time of observation between the first and second HIV test was 5386 months with an average inter test time of 4.2 months per participant. 2) The incidence rate of HIV seroconversion during pregnancy in Mulago hospital is 3.3per 100 women years. Conclusions: 1) Having an HIV positive sexual partner is significantly associated with HIV seroconversion during pregnancy in Mulago hospital. Mothers with HIV positive partners were over eight times at risk of seroconverting than those with HIV negative partners. 2) Age, education status, employment status, presence of STIs, exposure to domestic violence and condom use, were not significantly associated with HIV seroconversion in HIV negative pregnant women attending antenatal in Mulago Hospital.