Pregnant and Breastfeeding Women

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Are pregnant women at greater risk of developing serious West Nile Virus?

No. Pregnancy does not increase a woman’s risk of developing serious WNV illness (80% of all individuals infected show no symptoms). As well, pregnancy does not increase the likelihood of contracting West Nile Virus because this is determined by the amount of time spent outdoors and the level of protection taken. Pregnant women, as with all individuals, should take personal protective measures to prevent mosquito bites.

Can a pregnant woman pass West Nile Virus to her unborn child?

A small number of cases provide some evidence that WNV can be transferred to a fetus from the mother. Research continues into this method of transmission.

Can West Nile Virus be transmitted in breast milk?

West Nile Virus has been isolated from breast milk samples from lactating women who are infected. However, it is unclear as to whether or not the child can contract the virus in this manner. Research continues in this area.

Is it safe to use DEET when pregnant or breast feeding?

As with chemical exposure in general, pregnant women should limit exposure to repellents. Although, recent studies have shown that DEET accumulation in the fetus is low and that use is safe in later stages of pregnancy (2nd - 3rd trimester), non-chemical preventative measures should be considered. There is no indication that there is a hazard to the nursing child associated with the use of DEET by lactating women.

Source: Health Canada, Ontario Ministry and Health and Long Term Care, Centers for Disease Control