Prevalence and predictors of early gestational weight gain associated with obesity risk in a diverse Australian antenatal population: a cross-sectional study

BACKGROUND: Excess gestational weight gain (GWG) leads to adverse short- and long-term consequences for women and their offspring. Evidence suggests that excess GWG in early pregnancy may be particularly detrimental, contributing to the intergenerational cycle of obesity. The primary outcome was to investigate the prevalence and predictors of excess GWG in early pregnancy, and if women understand the risks to themselves and their offspring stratified by maternal body mass index (BMI). METHODS: This was a secondary analysis (n = 2131) of a cross-sectional study (n = 2338) conducted over 6 months in 2015 of pregnant women attending antenatal clinics at four maternity hospitals across Sydney, Australia before 22 completed weeks gestation An self-completed questionnaire was used to investigate knowledge of expected weight gain in pregnancy, understanding of risks associated with excess GWG, self-reported anthropometric measures and socio-demographic data. RESULTS: One third (34.2%) of women gained weight in excess of the recommendations by 22 completed weeks gestation. Women who were overweight (OR: 1.69, 95% CI: 1.33–2.14) or obese (OR: 1.64, 95% CI: 1.20–2.24) pre-pregnancy were more likely to gain excess weight in early pregnancy compared to normal weight women; as were women from lower socio-economic areas (OR: 1.89, 95% CI: 1.49–2.41). Half (51%) the women were unsure about the effect of excess GWG on their baby; 11% did not believe that excess GWG would affect the weight of the baby and 14% did not believe that excess GWG would affect longer term outcomes for their baby. Women who gained weight above the recommendations were significantly more likely to believe that excessive GWG in pregnancy would not have any adverse future effect on health outcomes or weight of their baby. CONCLUSIONS: The women at particular risk of excess early GWG are those who are overweight and obese and/or residing in lower socio-economic areas. These women need to be targeted for appropriate counselling preconception or in early pregnancy. Given the significant adverse outcomes associated with excess GWG in early pregnancy, preconception or early pregnancy counselling with respect to GWG and intervention research regarding best approach remains a public health priority. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12884-017-1482-6) contains supplementary material, which is available to authorized users.