My neighborhood pools opened this week for summer and my family couldn’t be more excited. Unfortunately, mosquitos are popping up again and reminding me of the importance of discussing insect repellants with my friends, families, and patients.
Many women who never wear insect repellants have recently become interested in these products because of the news coverage of the Zika virus. The Zika virus was introduced to the world during the most recent Olympic games in Brazil. Mosquito bites were linked to severe birth defects and the Zika virus was identified.
The number of pregnant women with laboratory evidence of possible recent Zika virus infection and the number of fetuses/infants with Zika virus–associated birth defects continues to increase in the United States. About 1000 pregnant women in the US were diagnosed with Zika virus infection last year. Of these pregnancies, birth defects were reported in 15%. Congenital microcephaly, or severely small head in the affected child, has been a hallmark of intrauterine infection with Zika virus. However, the full clinical spectrum and severity of Zika remains unknown. Others have recently reported much lower rates of confirmed Zika virus in other parts of the US and no confirmed fetal or neonatal infections, which puts some doubt on the true prevalence of this widely publicized virus. The field of perinatal Zika virus infection is evolving and we continue to learn more about the virus as well as the risk of disease.
Insect repellants can be a good option for reducing your exposure to mosquitos and tics. The EWG has published excellent resources for consumers to learn about what is in their bug repellent.
My family uses DEET. It protects you against tics and mosquitos. DEET is the only insect repellant that has been tested on pregnancy women. The children of mothers who used DEET in their second and third trimesters showed no birth defects, changes in body size or developmental problems. No studies have examined the children of women who applied DEET during their first trimester. However, at toxic doses, DEET has been associated with seizures and neurological damage. Although this risk is scary, The EPA reports that this risk is very low- 1 per every 100 million persons. As with medications, I tend to recommend limiting the use of multiple products in order to limit exposure to multiple chemicals. Choose one insect repellant and stick with it.
A more natural alternative is also available as oil of lemon eucalyptus. The tree extract is refined to intensify the concentration of the naturally occurring substance para-menthane-3,8-diol (PMD) from 1 to 65 percent. The resulting oil is very different from unprocessed tree oil. Some testing shows that concentrations of 20 to 26 percent PMD may perform as well as 15 to 20 percent DEET against both mosquitoes and ticks (Barnard 2004, Consumer Reports 2010). I think it is important for us to recognize the limited safety data available on essential oils in pregnancy and in children. Refined oil of lemon is classified as a possible biochemical pesticide. Oil of lemon eucalyptus and essential oils have disadvantages but is a good choice for people who want a botanically based bug repellant. EWG recommends that consumers who are in high-risk areas for bug-borne disease or need long-lasting, effective bug protection avoid botanically-based bug repellents, aside from Oil of Lemon Eucalyptus. In other cases, you may find it worth your while to try botanical repellents to identify one that works well for you.
What you can do:
- Avoid exposure to mosquitos: use insect repellants with <50% DEET when trying to conceive and during pregnancy. More is not better. My family uses 30%.
- Wash your hands well after applying insect repellant. Wash repellant-coated skin at the end of each day.
- You and your partner should avoid travel to areas with Zika virus when trying to conceive and during pregnancy. Discuss your travel plans with a physician if there is any question about the safety of travel. Talk to your physician if you or your partner are concerned that you have been exposed to the Zika virus.
For more information:
- NY Times Article
- CDC– includes maps of affected regions