The association between mid- pregnancy body mass index and socio economic status of women: evidence from Australia

Abstract

Objective: To examine the association between mid-pregnancy body mass index (BMI) and socio-economic status (SES) of pregnant women in Australia. Design: A large scale randomized control trial (RCT). Data were analysed using descriptive statistics and multivariate Probit regression models (Probit and Ordered Probit) controlling for maternal age, location of the hospital, and the treatment effect was performed for the analysis. Setting: Pregnant women who were registered in 5 perinatal centres in Australia between 2005 and 2008 were recruited. Subjects: 2399 pregnant women with singleton pregnancy at < 20 week gestation. Results: There was a negative association between mothers’ involvement in a professional employment and maternal mid-pregnancy obesity and overweight. Fathers’ employment as a professional was also significantly and negatively related to maternal BMI. Mother’s education was positively associated with mid-pregnancy BMI. Maternal smoking and drinking behaviour during pregnancy were significantly linked to obesity and underweight, respectively. A significant positive association was found for the Asian and the Aboriginal cohorts. Conclusions: Lower socio-economic status and poor health behaviours during pregnancy are associated with maternal obesity and overweight. Policies and interventions aiming at improving awareness and uplifting socio-economic status of pregnant women have the potential to lower the likelihood of being obese and overweight during pregnancy.