[The Environment and Childhood Research Network ("INMA" network): study protocol].

Increasingly greater evidence exists as to the influence which diet and exposure to low doses of toxic substances during the prenatal stage and early childhood has on health and well-being throughout later stages of life. Following the WHO and European Union recommendations in 2003, the Cooperative Environment and Childhood Research Network was set up to study the effects of the environment and diet on fetal and early childhood development in different geographical areas of Spain. This Network integrates different multidisciplinary research groups and is comprised of six cohorts--three pre-existing and three de novo--which will follow up prospectively 3,600 pregnant women, from the start of pregnancy up to age 4-6 years of the child. This network's general objectives are: (1) To describe individual exposure to toxic substances in the environment during gestation and early childhood. (2) To evaluate the effects of exposure to toxic substances and diet on fetal and early childhood development. (3) To evaluate the interaction among toxic, nutritional and genetic factors in fetal and early childhood development. The follow-up is done every three months during gestation, at birth, at age one and up to age four or six. The information is gathered by means of questionnaires, clinical data, physical examinations, echographs, biomarkers and environmental measurements. The general characteristics of the network and a description of the current situation of each one of the cohorts are provided in this study.