Is DEET insect repellent safe during pregnancy?

What does the evidence say about DEET insect repellent during pregnancy?

1. Less than 10 percent of the DEET applied to skin passes through into the bloodstream. 1
2. Used appropriately, DEET is not expected to increase the chance of birth defects, and is not expected to cause preterm delivery before week 37 or low birth weight. 1
3. A study of 449 people who used recommended daily doses of DEET through the second and third trimesters found no increase in problems with their babies' growth or development in the first year of life. 1
4. Regulatory reviews concluded DEET has low acute toxicity and is not considered a developmental or reproductive toxicant, and its effectiveness rises with concentration but plateaus around 50 percent, so stronger is not better. 2
5. Recommended use is a concentration of 30 percent or less, applying sunscreen first when both are needed, avoiding combined sunscreen-repellent products, and not reapplying more often than the label says. Permethrin goes on clothing, never on skin. 2

Is DEET insect repellent safe in each trimester?

• First trimester. There is no trimester where repellent is off limits, and the infections it guards against matter most early. Use the lowest concentration that covers the time you will be outside rather than the strongest bottle on the shelf.
• Second trimester. This is when most people travel, and it is also when the largest reassuring study sits: 449 people used recommended daily doses through the second and third trimesters with no growth or development problems in their babies at one year.
• Third trimester. Nothing changes now. If you are using sunscreen too, put the sunscreen on first and the repellent second, and skip the products that combine both.