1. Departments of Obstetrics and Gynecology (T.M., M.V., A.P., A.-L.H., E.S.-L.), University of Oulu, 90014 Oulu, Finland
2. Institute of Health Sciences (T.M., M.-R.J.), University of Oulu, 90014 Oulu, Finland
3. Department of Child and Adolescent Health (A.P., H.-M.S., A.B., M.-R.J.), National Public Health Institute, 90101 Oulu, Finland
4. Clinical Chemistry (A.R.), University of Oulu, 90014 Oulu, Finland
5. Department of Epidemiology and Public Health (M.-R.J.), Imperial College London, London SW7 2AZ, United Kingdom