Since early pregnancy, mothers and children have provided biological samples including blood, urine, hair, toenails, teeth, saliva and placenta. To ensure maximum efficiency of sample use, each sample has been divided into small aliquots and stored to ensure long-term preservation. The biobank is summarized in Supplementary Table S2 (available as Supplementary data at IJE online); full details of the ALSPAC biobank including a list of child samples and the assayed results are available on the study website.9
