Association between pre-pregnancy body mass index and socioeconomic status and impact on pregnancy outcomes in Korea

Aim: To compare socioeconomic status and pregnancy outcomes in relation to different pre-pregnancy body mass index (BMI) levels, and to determine whether gestational weight gain is related to socioeconomic status and pregnancy outcomes. Methods: This was a retrospective cohort study of 3554 singleton pregnancies. Gravidas were grouped into three BMI categories and in three gestational weight gain categories. We performed multivariate analyses for the associations between pre-pregnancy BMI, gestational weight gain, socioeconomic status, and pregnancy outcomes. Results: Overweight gravidas had shorter gestational weeks, decreased birthweight, and increased frequency of preterm birth (P < 0.05). There were higher percentages of low levels of education and low economic status in the overweight gravidas and their husbands (P < 0.05). There were also higher percentages of low levels of education in gravidas with a low weight gain during pregnancy and their husbands, and gravidas with low weight gain had increased frequency of preterm deliveries (P < 0.05). Overweight gravidas had a higher risk for preeclampsia (adjusted OR, 2.4) and gestational diabetes (adjusted OR, 2.0). Overweight gravidas and women with excessive weight gain during pregnancy had higher risks for cesarean section (unadjusted OR, 1.6), macrosomia (unadjusted OR, 2.7) and large for gestational age (LGA) (adjusted OR, 2.4). A higher risk for small gestational age (SGA) fetuses existed in normoweight gravidas and gravidas with low weight gain during pregnancy (unadjusted OR, 2.8). Conclusion: Overweight gravidas were associated with low education status, low economic status, and adverse pregnancy, whereas low weight gain during pregnancy was associated with low education status of the gravida and her husband, preterm delivery, and SGA.