OC12.03: Maternal Obesity and Congenital Heart Defects in the Offspring: a Danish Nationwide Cohort Study

To evaluate the association between maternal body mass index (BMI) and congenital heart defects (CHDs) in the offspring when including live births, stillbirths and terminated pregnancies from unbiased register data. A nationwide cohort study of all pregnancies in Denmark from June 1, 2008 to June 1, 2018. All data on maternal and offspring characteristics were retrieved from the Danish Fetal Medicine Database. This database includes prenatal screening results as well as postnatal diagnoses. Of the 547 235 singleton pregnancies included in the cohort, 5498 had CHDs (1.00%) and 1227 were defined as severe CHDs (0.22%). In total, 35% of the women had an early-pregnancy BMI ≥ 25 kg/m2, and 13% were obese (BMI ≥ 30 kg/m2). Among all pregnancies, maternal overweight or obesity were significantly associated with a moderate higher risk of any CHDs (aRR 1.18-1.76) and severe CHDs (aRR 1.21-1.77) in the offspring compared to women with a normal BMI. See table 1. This study present the first large-scale nationwide cohort including also stillbirths and terminated pregnancies. These results add to previous knowledge about association between maternal obesity and a moderate higher risk of CHDs in the offspring.