Chemical insect repellents
(Date: May 2018. Version: 2)
This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by the UK Health Security Agency (UKHSA) on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.
What are they?
Insect repellents contain chemicals to keep biting insects away and are applied to clothes, exposed skin, and bed nets.
What should I do if I am travelling to an area where Zika virus, Malaria or Lyme disease is common?
Where possible, pregnant women should avoid areas where there is a high risk of an insect bite causing a serious infection such as Zika virus, malaria (transmitted by mosquitos) or Lyme disease (transmitted by ticks - be aware that ticks are most commonly found in forest fringes, forest glades, riverside meadows and marshland, and forest plantations with brushwood and shrubbery). If this is not possible, use of chemical insect repellents during pregnancy is advised. Other non-chemical methods to reduce the chance of being bitten (e.g. staying indoors at the times of day when mosquitos are most active, using bed nets impregnated with insecticide to avoid mosquito bites, and minimising skin exposure when outdoors by wearing long sleeves and trousers and tucking trousers into socks) should always be used in conjunction with chemical insect repellents.
It is particularly important to avoid becoming infected with malaria, Zika virus or Lyme disease when pregnant. The risks to you and your baby from these illnesses are likely to be far greater than any risk from using a chemical insect repellent in pregnancy. Although Zika virus usually causes a relatively mild illness in individuals who are infected through a mosquito bite, it can cause potentially severe brain abnormalities in unborn babies of some women who are infected during pregnancy. Please refer to our bump on Zika virus which contains more detailed information and advice.
Are there any insect repellents that are recommended for use in pregnancy?
DEET (in brands including Autan®, Jungle Formula®, Ultrathon®, Repel®, Insectishield®) is currently recommended for use by all pregnant women who are travelling to areas where malaria and Zika virus are present. Pregnant women spending time outdoors in areas where there is a risk of Lyme disease from tick bites may also wish to use DEET.
A very small number of studies have examined DEET use during pregnancy. Whilst these studies do not suggest that use of DEET in pregnancy to prevent insect bites is harmful to a baby in the womb, until more scientific evidence is available it is advisable to only use DEET when needed and to follow the manufacturer’s instructions regarding the application of DEET. It is also recommended that insect repellents are washed off once you are no longer at risk of being bitten.
Can using DEET in pregnancy cause birth defects in my baby?
No link between DEET use in pregnancy and having a baby with a birth defect is known about; however no scientific studies have specifically investigated this.
One study suggested that hypospadias (where the opening on the penis is on the underside rather than at the tip) was more common in male babies born to mothers who had used various different insect repellents during early pregnancy. Although some women in this study had used DEET, these women were not analysed separately. This study does not show that hypospadias is caused by DEET.
Can using DEET in pregnancy cause my baby to be small at birth (low birth weight)?
There is no known link between using DEET in pregnancy and having a low birth weight baby (<2500g), however no studies have specifically investigated this.
Two studies have provided evidence that that using DEET in pregnancy does not affect the baby’s growth in the womb. More research is ideally required to confirm these findings.
Can using DEET in pregnancy cause other problems for my baby?
The only study which investigated problems after birth showed that babies whose mothers had used DEET during pregnancy were no more likely to die before the age of one, or to have abnormal brain development, than babies whose mothers had not used DEET during pregnancy.
What other insect repellents are available?
Picaridin
Picaridin is a similar type of insect repellent to DEET. No studies have been carried out to examine the possible effects on an unborn baby of picaridin use during pregnancy. In certain situations, for example if DEET was not available, you may still be advised to consider using picaridin if the risk of malaria or another serious illness from insect bites is high.
PMD-containing insect repellents
PMD-containing insect repellents are not as effective as DEET and are therefore not recommended for use in areas where there is a risk of malaria. No studies have been carried out to examine the safety of PMD use during pregnancy.
Permethrin
Permethrin is not sold as an insect repellent in the EU, but is sold in countries where mosquito bites can spread disease and is often used to kill mosquitos indoors and to impregnate bed nets, clothing etc. In the UK, permethrin is used in the treatment of scabies. For information on the use of permethrin in pregnancy please see the bump leaflet on treatment of scabies in pregnancy.
Will my baby need extra monitoring during pregnancy?
As part of their routine antenatal care most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects and to check the baby’s growth.
There is no evidence that using insect repellents during pregnancy will cause any problems that would require extra monitoring for your baby.
Are there any risks to my baby if the father has used insect repellents?
We would not expect any increased risk to your baby if the father used insect repellents before or around the time you became pregnant.
Who can I talk to if I have questions?
If you have any questions regarding the information in this leaflet please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.
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General information
Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks. They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.
Medicines use in pregnancy
Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby. There are, however, some medicines that can harm a baby’s normal development. How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.
If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.
When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.
Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.
www.medicinesinpregnancy.org