What is DEET?

• It is the active ingredient in many common brands of insect repellant.
• Most insect repellants contain 10-25% DEET in the form of a lotion, spray, or oil that is put on skin or on clothing.

Is DEET safe to use while pregnant?

• There have been case reports of abnormal pregnancy outcomes after the mother used DEET during pregnancy – but no connection has been made between those outcomes and the exposure to DEET.
• There have been no human studies on first trimester exposure to DEET.
• Studies on second and third trimester exposure to DEET have shown that there is no increase in birth defects or problems with the baby’s growth and development in the first year.
• DEET is absorbed, crosses the placenta, and deposits in fetal tissue in small concentrations – with no negative effects.  
• Based on animal studies, exposure to DEET would not increase the risk of birth defects.
• The Centre for Disease Control and Prevention (CDC) recommends pregnant women use the following precautions:
• Always follow the recommendations on the label of the repellent.
• Do not apply repellent under clothing. If repellent is applied to clothing, wash treated clothing before wearing again.
• Use enough repellent to cover exposed skin or clothing.
• Do not apply repellent to cuts, wounds, or irritated skin.
• Do not spray aerosol or pump products in enclosed areas (ex: bedroom, bathroom, kitchen).
• Do not spray aerosol or pump products directly to your face – spray your hands then rub them carefully over the face, avoid your eyes and mouth.
• Use the lowest percentage of DEET products possible for effective protection.
• Wash skin with soap and water immediately upon returning indoors and /or protection is no longer needed.
• Minimize exposure to bites by limiting outdoor activity at dusk and dawn.
• Wear light coloured clothing, long sleeve shirts and long pants, tuck pants into socks and button shirt cuffs for extra protection.  
• Eliminate any stagnant water where mosquitoes can breed near your home.
• Assess the level of risk of exposure versus the risk of adverse effects during pregnancy and use the guidelines outlined in the DEET Application Chart shown below:

Considerations for the West Nile Virus Season:    

• With the concern of the West Nile Virus and the chance of infection from mosquito bites, personal protection with the application of DEET containing products are recommended for people over 6 months of age.
• There have been no human studies in the first trimester of pregnancy demonstrating the safety of DEET in the effective concentrations of 20 –30%.
• Products containing higher concentrations of DEET do not provide greater protection – they only last longer.
• To minimize exposure, you should use the lowest level of concentration to give protection for the time you will be outside.
• It is important to consider that the benefits of using DEET during pregnancy outweigh the risks of using DEET.

Breastfeeding mothers

• DEET has not been reported to cause problems in nursing babies.
• Ensure that skin and hands are well cleansed after applying DEET before feeding.