Hui SYA, et al. - In this retrospective cohort study, researchers explored the link between BMI and the incidence of rubella nonimmunity among pregnant women with regard to the World Health Organization categories. Study participants were 117,063 eligible gravidas, managed between 1998 and 2015 in a university hospital of Hong Kong, China. They found that gravidas with high BMI were more likely to be nonimmune if born in Hong Kong compared with those born outside of Hong Kong. The findings from the present study suggested that high maternal BMI (≥ 25.0 kg/m²) was correlated with decreased rubella immunity, an effect confined to gravidas with almost complete vaccine coverage in childhood.