Insect Repellent (DEET)
Everyday exposureHome & environmentAlso called · 7 names▾▴
DEET, bug spray, mosquito repellent, tick repellent, insect spray, N,N-diethyl-meta-toluamide, m-DET
Home environment exposure
General information · effects depend on amount, timing, and how it is used. About these sources
- Topical
Research strength: 3 / 5
MotherToBaby says the evidence is limited and that DEET used as directed is not expected to increase birth-defect chances. Dugas et al. (2010) reported an association between first-trimester insect-repellent use and hypospadias, a difference in the opening of the penis. The study did not identify the products' ingredients or use frequency, and mothers were interviewed years after the birth. CDC and ACOG recommend EPA-registered repellents, including DEET, during pregnancy when used as directed. MotherToBaby says DEET miscarriage studies have not been done. Ask your provider about your situation.
Last reviewed: 2026-10-14
Sources
- MotherToBaby: N,N-diethyl-meta-toluamide (DEET)Teratology service
- MotherToBaby: Insect RepellentsTeratology service
- Dugas et al., Occupational and Environmental Medicine 2010 (case-control study)US government
- CDC Yellow Book: Mosquitoes, Ticks, and Other ArthropodsUS government
- CDC Yellow Book: Pregnant TravelersUS government
- ACOG: Travel During PregnancyProfessional society
Research strength: 3 / 5
MotherToBaby says DEET used as directed is not expected to increase birth-defect chances, while also noting that the evidence is limited. McGready et al. (2001) studied 1.7 g/day DEET use in the second and third trimesters as part of a randomized trial with 897 women overall; the trial found no difference in infant survival, growth, or development at birth or one year. The trial does not address first-trimester use or outcomes after one year. CDC and ACOG recommend EPA-registered products, including DEET, as directed during pregnancy. Ask your provider about your situation.
Last reviewed: 2026-10-14
Sources
- MotherToBaby: N,N-diethyl-meta-toluamide (DEET)Teratology service
- MotherToBaby: Insect RepellentsTeratology service
- McGready et al., American Journal of Tropical Medicine and Hygiene 2001 (randomized trial)US government
- CDC Yellow Book: Mosquitoes, Ticks, and Other ArthropodsUS government
- CDC Yellow Book: Pregnant TravelersUS government
- ACOG: Travel During PregnancyProfessional society
Research strength: 3 / 5
MotherToBaby says DEET used as directed is not expected to increase birth-defect chances, while also noting that the evidence is limited. McGready et al. (2001) studied 1.7 g/day DEET use in the second and third trimesters as part of a randomized trial with 897 women overall; the trial found no difference in infant survival, growth, or development at birth or one year. The trial does not address first-trimester use or outcomes after one year. CDC and ACOG recommend EPA-registered products, including DEET, as directed during pregnancy. Ask your provider about your situation.
Last reviewed: 2026-10-14
Sources
- MotherToBaby: N,N-diethyl-meta-toluamide (DEET)Teratology service
- MotherToBaby: Insect RepellentsTeratology service
- McGready et al., American Journal of Tropical Medicine and Hygiene 2001 (randomized trial)US government
- CDC Yellow Book: Mosquitoes, Ticks, and Other ArthropodsUS government
- CDC Yellow Book: Pregnant TravelersUS government
- ACOG: Travel During PregnancyProfessional society
Insect Repellent (DEET) — Breastfeeding
Research strength: 1 / 5
MotherToBaby says DEET use while breastfeeding has not been studied, and illnesses spread by mosquitoes or ticks can affect a nursing parent and child. It says to follow the product label, avoid applying DEET over large areas, and keep it off the nipple to limit the baby's mouth contact. CDC also says EPA-registered repellents can be used during breastfeeding as directed and should be kept away from the nipple. Ask your provider about your situation.
Last reviewed: 2026-10-14
Sources
- MotherToBaby: N,N-diethyl-meta-toluamide (DEET)Teratology service
- MotherToBaby: Insect RepellentsTeratology service
- CDC: Other Environmental Exposures while BreastfeedingUS government
- CDC Yellow Book: Mosquitoes, Ticks, and Other ArthropodsUS government
- CDC Yellow Book: Pregnant TravelersUS government
- ACOG: Travel During PregnancyProfessional society
Pregnancy
McGready et al. (2001) assessed daily dermal DEET use at 1.7 g/day in the second and third trimesters in a double-blind randomized malaria-prevention trial with 897 participants overall. DEET users had a median total dose of 214.2 g per pregnancy (range 0-345.1 g). DEET was detected in 8% of cord blood samples (95% CI 2.6-18.2) from a randomly selected subgroup of 50 DEET users. The abstract reports no difference in infant survival, growth, or development at birth or one year. The study did not test first-trimester exposure or outcomes beyond one year. Dugas et al. (2010) studied 471 hypospadias cases and 490 controls; first-trimester insect-repellent use was associated with hypospadias (adjusted OR 1.81, 95% CI 1.06-3.11). The study did not identify ingredients or use frequency, so this is not a DEET-specific result. Mothers were interviewed in 2000-2003 about pregnancies involving children born in 1997-1998. MotherToBaby says studies have not been done to see whether DEET increases miscarriage chances.
Breastfeeding
MotherToBaby states that DEET use during breastfeeding has not been studied. The source review did not locate a DEET-specific LactMed entry, human milk-level study, or infant exposure study. CDC gives label-use and nipple-area instructions for EPA-registered repellents during breastfeeding, but does not report DEET milk levels or direct infant outcome studies.
DEET, also called N,N-diethyl-meta-toluamide or m-DET, is an active ingredient in many topical insect repellents. MotherToBaby describes it as effective against mosquitoes and ticks. This entry covers topical DEET products, not every insect-repellent ingredient or formulation.
What was tested
The pregnancy evidence includes one randomized trial of regular DEET use in the second and third trimesters (McGready et al., 2001; 897 participants overall) and a case-control study of insect-repellent use in the first trimester (Dugas et al., 2010; 471 cases and 490 controls; ingredients and frequency were not recorded). The absorption study by Selim et al. (1995) involved 12 adult male volunteers, two formulations applied to the forearm for 8 hours, and blood, urine, and feces collection for 5 days; it was not a pregnancy or breastfeeding study. No DEET-specific human breastfeeding study was located in the reviewed sources.
First-trimester insect-repellent use and hypospadias
- Source A says
- Dugas et al. reported an association between first-trimester insect-repellent use and hypospadias (adjusted OR 1.81, 95% CI 1.06-3.11). The study did not identify the products' active ingredients or frequency of use. (Dugas et al., Use of biocides and insect repellents and risk of hypospadias, Occupational and Environmental Medicine 2010)
- Source B says
- MotherToBaby says DEET used appropriately is not expected to increase birth-defect chances. CDC and ACOG recommend EPA-registered repellents, including DEET, as directed during pregnancy. (MotherToBaby: N,N-diethyl-meta-toluamide (DEET), CDC Yellow Book: Mosquitoes, Ticks, and Other Arthropods, ACOG: Travel During Pregnancy)
- Why they differ
- Dugas et al. asked about repellent use during pregnancies in 1997-1998 through telephone interviews in 2000-2003. The study did not record the active ingredients or frequency, so its association cannot be assigned to DEET. CDC and ACOG guidance concerns EPA-registered products used according to their labels and does not resolve first-trimester exposure to every repellent.
- What the evidence shows overall
- MotherToBaby describes the Dugas finding as low-reliability and says it did not prove that DEET caused the birth defect. The randomized DEET trial covered only the second and third trimesters and followed infants to one year. CDC and ACOG continue to describe EPA-registered repellents as usable as directed during pregnancy. First-trimester DEET evidence and longer-term child follow-up remain limited.
- MotherToBaby says to read and follow all label directions and precautions. It also describes using the lowest concentration that protects for the time outdoors as a way to lower exposure. (MotherToBaby: N,N-diethyl-meta-toluamide (DEET))
- CDC says to apply repellents only to exposed skin or clothing as the label directs, and not to cuts, wounds, or irritated skin. (CDC Yellow Book)
- CDC says breastfeeding mothers can use EPA-registered repellents according to the label, only when needed, and keep them away from the nipple area. (CDC: Other Environmental Exposures while Breastfeeding)
- ACOG says pregnant travelers can use EPA-registered sprays containing DEET or listed alternatives when used as directed. (ACOG)
General research, not specific to pregnancy.
CDC reports that EPA-registered repellents reduce insect bites when used as directed and that severe reactions are rare. CDC says DEET efficacy tends to peak around a 50% concentration, with no marked increase in protection time at higher concentrations.
- CDC says severe reactions to insect repellents are rare. For a rash or other reaction, it advises washing the product off with mild soap and water and stopping its use. (CDC Yellow Book: Mosquitoes, Ticks, and Other Arthropods)
- CDC says DEET efficacy tends to peak at approximately 50% concentration and that concentrations above that do not offer a marked increase in protection time against mosquitoes. (CDC Yellow Book: Mosquitoes, Ticks, and Other Arthropods)
- MotherToBaby: N,N-diethyl-meta-toluamide (DEET)Teratology serviceSecondaryPage dated 2025-04-01
- MotherToBaby: Insect RepellentsTeratology serviceSecondaryPage dated 2026-07-01
- CDC Yellow Book: Mosquitoes, Ticks, and Other ArthropodsUS governmentSecondaryPage dated 2025-04-23Independent check
- CDC: Other Environmental Exposures while BreastfeedingUS governmentSecondaryPage dated 2025-02-21Independent check
- CDC Yellow Book: Pregnant TravelersUS governmentSecondaryPage dated 2025-04-23Independent check
- ACOG: Travel During PregnancyProfessional societySecondaryIndependent check
- McGready et al., Safety of the insect repellent N,N-diethyl-M-toluamide (DEET) in pregnancy, American Journal of Tropical Medicine and Hygiene 2001US governmentPrimaryIndependent check
- Dugas et al., Use of biocides and insect repellents and risk of hypospadias, Occupational and Environmental Medicine 2010US governmentPrimaryIndependent check
- Selim et al., Absorption, metabolism, and excretion of N,N-diethyl-m-toluamide following dermal application to human volunteers, Fundamental and Applied Toxicology 1995PrimaryIndependent check
- ATSDR: Toxicological Profile for DEET (N,N-diethyl-meta-toluamide)US governmentSecondaryIndependent check
Last reviewed 2026-10-14
Independent check 2026-10-14
Not yet clinician-reviewed
Ask your provider about your situation.