Temporal trend of early pregnancy high body mass index in Australian women: risk factors and outcomes

Background There is a shift toward the increasing weight gain among women of reproductive age. Aim To assess changes in the prevalence of high body mass index (BMI) (including both overweight and obese) in early pregnancy in Australian women, and its risk factors and association with selected birth outcomes from 2011–2017. Methods Records of pregnant women who received antenatal care and gave birth at an Australian tertiary hospital during 2011–2017 were evaluated and trends of high BMI were investigated. Results The risk of high BMI at early pregnancy increased by 3% annually and rose from 37% in 2011 to 44% in 2017. The risk of high BMI was greater in women who were more than 35 years old, multiparous, were smoking during pregnancy, and who had neurological disorders. High maternal BMI was associated with greater risks of having assisted conception, caesarean section and larger neonate. Conclusion The rate of high BMI in early pregnancy increased between 2011–2017.