ALSPAC was established to understand how genetic, biological, environmental, social, psychological and psychosocial factors influence the health and development of children and their parents. ALSPAC is a multi-generation prospective cohort based in Bristol in the South West of England. More than 14, 000 women (G0) were enrolled in 1991 and 1992. Their partners (also G0), children (G1) and now grandchildren (G2) have been recruited and followed up over multiple timepoints. A wide variety of biological samples have been collected along with a vast array of exposure and outcome data collected via questionnaire, face to face clinics and through linkage to administrative data.

During the index pregnancy women were sent 3 questionnaires. Since then, over a period of some 25 years, women have been sent almost annual questionnaires asking about their own health and well-being. From 2008, women were invited to attend four focus clinical assessments. Assessments of the children have been administered frequently, with multiple data collection time points since birth. These include numerous child-completed questionnaires, a number of clinical assessments from the age of 7 years and further questionnaires about the child completed by the mother or other main caregiver. Partners of the mothers have also completed a number of questionnaires and been invited to one focus clinic assessment. The second generation (children of the children) have been and continue to be recruited with data collected via questionnaire and clinical assessment at multiple time points.

The study has multiple datasets arranged by cohort member, data type (usually questionnaire or clinic) and time point. In addition, the study reacted quickly to the COVID-19 pandemic and has multiple data collections available from March 2020.