First Exposure


Information last updated: October 2021

The baseline risk of major birth defects in Canada is 3-5%. This means that 3-5 out of 100 babies born in the general population in Canada will be born with a major birth defect. There are also baseline risks for miscarriages (15-25 out of 100 pregnancies), prematurity and other outcomes. The information provided will summarize if taking this drug is likely to change these risks. 

Summary: Approximately 1800 pregnancies with exposure to cetirizine during the first trimester were included in studies that examined rates of birth defects. Based on this, it is not expected that taking cetirizine in pregnancy will increase the risk of babies being born with major birth defects above the baseline risk. As well, the limited available information does not raise concerns for increased rates of other adverse pregnancy outcomes. To see more details please click on the tabs below.

Please consult with your health care provider if you are considering stopping or making any changes to your regular medications.

This information about cetirizine is of a general nature and about medical use and does not replace the medical care and advice of your healthcare provider. For questions on dose, timing, side effects, interactions, etc. please consult your healthcare provider. Additionally, please read the patient insert provided with your medication.

Although participants in the studies referenced below may have used cetirizine in various combinations, the studies usually do not provide detailed information on drug combinations.  This makes it challenging to comment on the safety of using this medication in combination with others during pregnancy or lactation.


First Exposure does not offer health care treatment. If you have an urgent question about your pregnancy or your baby’s health, you should contact your health care provider directly. If you don’t have a health care provider and you live in Ontario, you have a variety of health care options. In the case of an emergency, visit a hospital emergency room or call 911.