We include into the study women between 8–12 weeks of single pregnancy, not assisted with reproductive technology, and not expected to be finished as spontaneous abortion. All women with the serious chronic diseases specified in study protocol such as diabetes, hypertension, nephropathy, epilepsy and cancer are excluded from the study. The same refers to suspicion of serious child malformations known to exist at the inclusion into the study.

Study design and population
Polish Mother and Child Cohort Study is the prospective cohort study conducted in different regions of Poland. The final cohort is intended to comprise 1800 mother-child pairs to be recruited within 4-year period (2007-2011).
Assessment of exposure
Biological samples including saliva, urine, hair, blood, cord blood and breast milk are collected from study subjects. The exposure to heavy metals, polycyclic aromatic hydrocarbons and environmental tobacco smoke is assessed. It is also intended to explain the role of oxidative stress and nutritional status of the pregnant women on pregnancy outcome and children's health.
Follow-up of the children
The children are followed-up to the age of 2 years to determine long term effects of pre- and postnatal environmental exposures. The incidence of the upper and lower respiratory tract infections, middle ear diseases and symptoms of allergy among the child is identified. BSID-III is used for assessment of child neurodevelopment.