Definition of exposure variables, confounders and outcome variables from various registries (The National Registry of Patients, The National Registry of medical Products Statistics, The Danish Birth Registry, Statistics of Denmark and Cause of Death Registry) by International Classification of Dise

a1. The National Registry of Patients, 2. The National Registry of medical Products Statistics, 3. The Danish Birth Registry (includes births after 22 weeks), 4. Statistics of Denmark, 5. The Cause of Death Registry.
bRoutine recording of BMI started in 2004. Smoking status was recorded as a dichotomous variable and BMI in 5 categories: BMI under 18.5, BMI between 18.5–24.9, 24–29.9, 30–35 and BMI more than 35.
cHospitalization during pregnancy, if admitted more than one day