Insect Repellents and Pregnancy. Repellents containing active ingredients, such as DEET and picaridin, which have been registered with the EPA, are considered safe for pregnant and breastfeeding women.

Dear Tdc Nguyen,

According to the published literature, the data (human) is insufficient and inconclusive. So it is not predictable. If you want to extrapolate the preclinical data to humans, it not always safe prediction to apply for humans it as non-teratogenic. Since its been using for about more than 50 years and no direct case studies were reported regarding its teratogenic effects from human studies. So based on these information, it can be considered as non-teratogenic to humans. So it should be used until unless if it is necessary to be used during pregnancy. 

I hope this answer will help you.

Best Regards,

Dr. Uday Kumar Killi.

Absence of teratogenic effects in animal studies is not a garanty for inocuity in humans. We need to be a little more cautious and perform longitudinal observational studies in exposed populations rather than just making statements. Multinationales companies hide risks as their sole interest is profit.

Dear Colleague,

Studies in rats and rabbits haven’t showed any teratogenicity. DEET is now in use since a long time and there is no confirmed report of teratogenic effect in human. Still we are not able to certify that DEET has absolutely no teratogenic potential, but if there is one it must be extremely rare.  When coming to the question “should I use DEET during pregnancy?”, you must take in account on one side the benefit (protection against vector of a lot of disease with potential effect on the mother but also the fetus: malaria, dengue, zika, etc…) and on the other side the until now theoretical risk of a teratogenic effect.  You should only use it if it’s indicated.

Best regards

Dr Christian Dugauquier

Thanks so much everybody! I'd like to add some more evidence to this subject.

Many toxicological studies showed that DEET metabolism in human is similar to that in rats. When conducting a randomized controlled study in a large pregnant population, Rose McGready et al mentioned that according to the literature when rats received a high dose of DEET applied to their skins, an increasing in embryo mortality, decreased birth- weight, delayed development, and a high postnatal death rate was observed. Nevertheless, their works document the safety of DEET used regularly in the second and third trimesters of pregnancy. 

How about the first trimester of pregnancy? No evidence exists, although a lot of women of childbearing age are being concerned, because they aren't aware of their pregnancy and have been using this product. Furthermore, DEET with high concentration (50%, 75%, even 100%) has been sold widely without prescription.

Evidence- based medicine shows that over the many years of using DEET in pregnancy, in malaria endemic country like Nigeria, there has been no report of teratogenicity. But that could be a good work for collaboration to further confirm this.

Even with High concentrated solution, if it is used correctly (only when necessary and only on exposed skin), you will normaly never reach in humans the concentration used in rats and rabbits by Mac Gready and others in the 80's and 90's. 

4 to 17% of the applied dose passes into the blood,  It could cross the placenta, but levels seems to be lower  n the fetus.  DEET and metabolites are excreted quickly (within hours) through the urine. A small proportion is excreted in the feces.

All this is in favor of a very low risk for the fetus. We don’t expect very spectacular teratogenic effect, even if we cannot assume that it is 100 % safe.

Like proposed by Dr Nwangwa Eze, if you can conduct large survey on a great number of pregnancy, it could help to confirm the safety or to detect side-effect that are no frequent.

Best regards