BackgroundOverweight or obesity is detrimental during pregnancy. We studied time trends in the educational gradient of overweight and obesity among pregnant women. Differences in overweight and obesity by area of residence and country of birth were also examined.MethodsThe study was based on the Swedish Medical Birth Register between 1992 and 2010 and included 1,569,173 singleton pregnancies. Weight and height were registered during the first visit at the antenatal-care clinic. Data on education, country of birth, and area of residence were derived from registers with national coverage.ResultsIn 2008–2010, 32% of Swedish nulliparous pregnant women were overweight or obese. The relative risk of obesity among lower educated women compared to women with higher education increased from 1.91 (95% confidence interval: 1.85-1.97) in 1992–1995 to 2.09 (95% confidence interval: 2.05-2.14) in 2008–2010. There was an inverse linear relationship between risks of overweight or obesity, and population density and type of residence municipality. An excessive gestational weight gain according to the American Institute of Medicine was observed among 57-63% of the overweight or obese women, but there were small differences by education. Pregnant women born in Africa, Middle East or Latin America had higher risks of being overweight or obese compared to women born in Sweden.ConclusionsThe prevalence of obesity as well as the social inequalities in obesity during pregnancy increased in Sweden between 1992 and 2010. Further understanding of social inequalities and geographical differentials in health behaviours of pregnant women is needed when planning public health interventions.

The prevalence of overweight including obesity was stable among Swedish children between 2003 and 2011. Gradients in the determinants of overweight persisted. There was some evidence of a less steep socio-economic gradient in overweight in eight-year-old girls over time.

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