Bayesian Modelling on Incidence of Pregnancy among HIV/AIDS Patient Women at Adare Hospital, Hawassa, Ethiopia

HIV/AIDS is the most serious diseases human kind has ever faced and a public problem, particularly, for women of childbearing age. For HIV infected women, the prospects of getting pregnant and having an HIV negative baby could be significantly improved with the increasing of the availability of Antiretroviral Therapy (ART). Even though, ART treatment has shown significant effect of clinical importance to reduce the risk of mother to child transmission of HIV but, HIV infected Women remain poorly understood or they fear to be pregnant and having HIV negative child. To the authors’ knowledge, no study examined incidence of pregnancy among women on ART follow-up in Ethiopia. In response, we conducted a study to explore the incidence and potential predictors of pregnancy. The objective of this study was to investigate the incidence of pregnancy among HIV/AIDS patient women under ART follow-up. A retrospective cohort study was conducted based on secondary data that reviews or visits medical chart of HIV/ADIS patient women aged 15-49 years under ART follow-up from April 2008 to February 2015. Out of 720 total patient women, a sample of size 328 was selected by using simple random sampling technique. Bayesian estimation were used for binary logistic regression model to identify the significant factors of incidence of pregnancy. The Gibbs sampler algorithm was implemented by WinBUGS software to solve approximate properties of the marginal posterior distributions for each parameter in Bayesian estimation. The results of this study revealed 21.3% of women got pregnancy during the follow-up. From Bayesian logistic regression analysis, significant predictors of incidence of pregnancy were: WHO clinical stage, marital status, contraception use, number of child alive before ART follow-up, CD4 cell count, time of Antiretroviral Therapy (ART) follow-up, educational level, spouse's HIV status, occupation and age (at p=0.05). In this study, when age of the women increased, the probability of becoming pregnant was decreased and advanced WHO clinical stage were associated with decreased incidence of pregnancy. Time on ART was a strong predictor of becoming pregnant: longer time on ART was associated with increased probability of becoming pregnant. Educational level of women was positively related with incidence of pregnancy that is, women who had college and above educational level was more likely to become pregnant. When CD4 count increased, incidence of pregnancy also increased and married women had more chance to become pregnant. The predictors identified in this study