Presentation of recruitment sites in the Bidens study.

References for number of deliveries in the geographical area: Belgium: SPE (Studiecentrum Perinatale Epidemiologie) 2008. Iceland: The Icelandic Birth register for 2008. Denmark: http://www.sst.dk/Indberetning%20og%20statistik/Sundhedsdata/Foedsler_fertilitetsbehandling_og_abort/foedsler1.aspx. §Born at hospital Estonia: http://www.tai.ee/et/tegevused/registrid/meditsiiniline-sunniregister-ja-raseduskatkestus-andmekogu/statistika; Estonian Medical Birth Registry. Sweden regional data: http://www.socialstyrelsen.se/register/halsodataregister/medicinskafodelseregistret Norway: Medical Birth Registry. *Number of newborn ≥22 weeks gestation.