Maternal-Infant Research on Environmental Chemicals (MIREC) Study

Recent reports raise concerns about the number of environmental chemicals in our bodies. They also address the possible health effects that may be linked to the levels of these chemicals.

Reliable data on levels of environmental chemicals of concern in Canadians have been scarce. Now, major advances in the analysis of chemicals mean detection of extremely low levels of chemicals is possible in:

• hair
• body fluids
• human milk
• human tissues

It is common to find trace levels of chemicals in people's urine or blood. This is because we come across many of these chemicals in our everyday lives.

We know that high levels of some chemicals, such as lead and mercury, cause adverse health effects. Whether lower levels of exposure can also cause adverse health effects is not always clear.

The Canadian Health Measures Survey gives much-needed data on Canadians' exposure to many environmental chemicals. However, it does not focus on 2 of the most vulnerable groups: pregnant women and their babies.

Canada and other countries are studying pregnant women. The goal is to know more about levels of environmental chemicals and the possible health effects on:

• infants
• children
• mothers

Breast-feeding is understood to be the best method for feeding infants. However, we need to know more about breast milk, including its:

• nutritional content
• levels of environmental chemicals

Smoking in pregnancy has long been linked to adverse health effects on the baby, such as low birth weight. We need to know more about:

• whether smoking behavior changes during pregnancy
• the extent of exposure to tobacco smoke during pregnancy

The Maternal-Infant Research on Environmental Chemicals (MIREC) Research Platform was designed to address these data gaps. Scientists at Health Canada, with their academic and clinical research colleagues, designed the platform.

The platform includes the MIREC study, several MIREC biobank projects and the follow-up studies:

• MIREC-ID
• MIREC-CD3
• MIREC-CD Plus
• MIREC-ENDO

Data collection is complete for all the studies except for MIREC-ENDO and some of the Biobank projects.