DEET: Best for Preventing Bug Bites, Safe for Pregnant Women

September 07, 2021

pregnant woman in woods wearing tank top and skirt

DEET has been commercially used as the active ingredient in most insect repellants since the 1950s, but over the years, questions have come up about whether DEET is safe for pregnant women.

DEET (N,N-diethyl-3-methylbenzamide or N,N-diethyl-M-toluamide) has been studied extensively for safety, and is the most effective at preventing bug bites. It's also perfectly safe for pregnant women to use, says OB/GYN Christopher Nau, MD, of UH's Division of Maternal-Fetal Medicine

“Data on the use of DEET is reassuring,” Dr. Nau says. “Studies in rats and rabbits have not demonstrated an increased risk of birth defect or pregnancy complications, even using doses that are given orally and exceed the doses used to repel insects.”

Dr. Nau adds that the use of DEET to prevent insect-born infection in pregnant women is recommended by the U.S. Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists.

Insect Bites Carry Diseases

DEET’s benefits are significant because mosquitos and ticks are more than annoyances. They carry a variety of diseases, which can be particularly troublesome for pregnant women. The CDC receives about 30,000 reports of Lyme disease, transmitted by deer ticks, every year. Diseases spread by mosquitos include Zika virus, West Nile virus, dengue and malaria. West Nile virus has been found throughout the continental United States.

For those who would rather not use DEET, there are alternatives. They include picardin, IR3535, oil of lemon eucalyptus (P-menthane-3,8-diol), paramenthane-diol, or 2-undecanone, Dr Nau says.

“They all are recommended for use during pregnancy, though some of the data on the individual agents may not be as robust as the data on the use of DEET,” Dr. Nau says.

How To Use DEET

Insect repellants come in many forms. Dr. Nau says you should stick with sprays and lotions. Wearable repellants such as bracelets and electronic devices have not been proven to be effective.

Pregnant women should follow the same instructions for using repellants as everyone else. Overexposure is rare, but some people exposed to excessive amounts have experienced skin rashes, blisters and irritation, according to the CDC.

“More serious toxicity has been reported, but is generally confined to ingestion or other very large exposure that exceeds the amount of exposure with regular, recommended use,” Dr. Nau says.

When choosing a repellant, the most important thing to find one that has research backing up its effectiveness. Many herbal products and vitamins on the market are touted as being effective, Dr. Nau says, but don’t have data backing up the claim, including data on whether they are safe during pregnancy.

The U.S. Environmental Protection Agency (EPA) provides a database of registered insect repellants and a search tool to find a repellant that’s right for you.

Other Ways to Avoid Insect Bites

Strategies to avoid insect bites are especially important for those who choose not to use repellants.

“Avoid being outside during dawn and dusk when mosquitoes are most active, and wear long-sleeved shirts and pants to lower your risk,” Dr. Nau says.

As for protection against tick bites, avoid walking through woods, tall grass and brush with skin exposed. Wear pants, socks and a long-sleeved shirt on nature hikes. Tuck pants legs into socks or boots, and stay near the center of the path.