Social inequality in pre-pregnancy BMI and gestational weight gain in the first and second pregnancy among women in Sweden.

BACKGROUND: High pre-pregnancy body mass index (BMI) and inappropriate gestational weight gain (GWG) are associated with adverse short and long-term maternal and neonatal outcomes and may act as modifiable risk factors on the path to overweight/obesity, but their social patterning is not well established. This study investigates the association of education with BMI and GWG across two consecutive pregnancies. METHODS: The study includes 163,352 Swedish women, having their first and second singleton birth in 1982-2010. In both pregnancies, we investigated the association of women's education with (1) pre-pregnancy weight status and (2) adequacy of GWG. We used multinomial logistic regression, adjusting for child's birth year, mother's age and smoking status. RESULTS: Overall, the odds of starting either pregnancy at an unhealthy BMI were higher among women with a low education compared to more highly-educated women. Lower education also predicted a greater increase in BMI between pregnancies, with this effect greatest among women with excessive GWG in the first pregnancy (p