Associations between antenatal booking body mass index and postnatal placental weight: maternal health implications in HIV-positive and HIV-negative pregnant women in Uyo, Akwa Ibom state, Nigeria

Abstract

Introduction and aim. Maternal body mass index (BMI) and placental weight are important indicators of maternal-fetal health, and their relationship may be influenced by HIV status. This study examined the association between antenatal booking BMI and postnatal placental weight among HIV-positive and HIV-negative pregnant women in Uyo, Nigeria. Material and methods. We conducted a retrospective comparative cross-sectional study based on medical records review of 143 women (48 HIV-positive, 95 HIV-negative) who attended antenatal care and delivered at the University of Uyo Teaching Hospital between December 2015 and May 2016. BMI was calculated from early pregnancy weight and height measured at the first antenatal visit; whole placental weight was measured post-delivery. Linear regression, adjusted for gestational age, evaluated associations between BMI, HIV status, and placental weight. Results. Among 143 participants (48 HIV-positive, 95 HIV-negative), mean placental weight was significantly lower in HIV-positive women (602.94±174.92 g) compared with HIV-negative women (684.53±139.38 g; p=0.012). Gestational age was the strongest predictor of placental weight (p=0.009), while HIV infection was independently associated with lower placental weight (p=0.016). BMI was positively but not significantly associated with placental weight. Conclusion. Antenatal BMI and postnatal placental weight are interrelated, with differing patterns by HIV status. These findings underscore the need to integrate routine nutritional assessment and targeted HIV care into antenatal programs to support healthy placental growth and improve pregnancy outcomes in high HIV-prevalence populations.