Objective: Optimal gestational weight gain (GWG) leads to better outcomes for both the mother and child, whereas excessive gains can act as a key stage for obesity development. Little is known about social inequalities in GWG. This study investigates the influence of education level on pre-pregnancy body mass index (BMI) and GWG.Design:Register-based population study.
Participants: Four thousand and eighty women born in Sweden who were a part of the third generation Uppsala Birth Cohort Study. Register data linkages were used to obtain information on social characteristics, BMI and GWG of women with singleton first births from 1982 to 2008.
Main outcome measure: Pre-pregnancy BMI and the Institute of Medicine's (IOM) categories of GWG for a given pre-pregnancy BMI. Results were adjusted for calendar period, maternal age, living arrangements, smoking, history of chronic disease and pre-pregnancy BMI when appropriate.
Results: Although most women (67%) were of healthy pre-pregnancy BMI, 20% were overweight and 8% were obese. Approximately half of all women in the sample had excessive GWG, with higher pre-pregnancy BMI associated with higher risk of excessive GWG, regardless of education level; this occurred for 76% of overweight and 75% of obese women. Lower educated women with a healthy pre-pregnancy BMI were at greater risk of excessive GWG-odds ratio 1.76 (95% confidence interval 1.28-2.43) for elementary and odds ratio 1.32 (1.06-1.64) for secondary compared with tertiary educated, adjusted for age and birth year period. Nearly half of women with an elementary or secondary education (48%) gained weight excessively.
Conclusion: Education did not provide a protective effect in avoiding excessive GWG among overweight and obese women, of whom ∼75% gained weight excessively. Lower educated women with a BMI within the healthy range, however, are at greater risk of excessive GWG. Health professionals need to tailor their pre-natal advice to different groups of women in order to achieve optimal pregnancy outcomes and avoid pregnancy acting as a stage in the development of obesity.