Use of insecticides in pregnancy

(Date: January 2018. Version: 1)

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 insecticides?

Insecticides are chemicals that kill insect pests. They may be used around the home, for example to eradicate wasps, ants, or fleas, as treatments applied to the body, for example to eradicate lice or scabies, and on companion animals to treat fleas, ticks, and lice. They are used in agriculture and in the garden to kill insects that damage crops and plants. Outside the UK they are used in the environment to kill insects such as mosquitos that spread disease. Commonly used types of insecticide include carbamates, organophosphates, pyrethrins/pyrethroids, and neonicotinoids.

There are separate bump leaflets on treatment of head lice and scabies in pregnancy

Is it safe to use an insecticide in pregnancy?

Although there are numerous published studies on the possible effects of insecticide exposure in pregnant women and in fathers around the time of conception, there are many problems with the way that this information has been collected and analysed, which mean that the results are difficult to interpret and may not be reliable.

For example:

• In many of the studies, exposure to an insecticide is assumed (due to the mother’s or father’s job or place of residence) rather than confirmed
• Many people are exposed to several insecticides at the same time which means that the effects of any single insecticide are difficult to determine
• Additionally, women with exposure to high levels of insecticides may have a higher chance  of other lifestyle factors (such as smoking and poverty) that can independently increase the risk of poor pregnancy outcomes

The effects of insecticide exposure during pregnancy and in men around the time of conception are therefore difficult to determine.

When deciding whether or not to use an insecticide during pregnancy it is important to weigh up how necessary this is to your health/wellbeing against the possible risks to you or your baby, some of which will depend on how many weeks pregnant you are. If you use an insecticide (whether or not you are pregnant) you should follow the manufacturer’s instructions for use, especially regarding quantities, level of ventilation required for indoor use, and use of personal protective equipment such as gloves or a face mask.

Women exposed to insecticides at work should follow local health and safety protocols to minimise exposure and should arrange for their employer to carry out a risk assessment.

What if I have already used an insecticide during pregnancy?

If use of the insecticide did not cause any symptoms of toxicity you do not need to take any action. If you experienced any unusual symptoms/toxicity after exposure to an insecticide in pregnancy you should report this to your doctor who may decide to contact UKTIS for further advice.

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 good evidence that using an insecticide as directed during pregnancy causes any problems that would require extra monitoring of your baby. However, women who have experienced toxic symptoms and/or been exposed to very high levels of an insecticide during pregnancy may receive additional monitoring to ensure that the baby is growing and developing as expecting.

Are there any risks to my baby if the father has used an insecticide?

Studies that have investigated possible links between exposure of the father to insecticides around the time of conception and birth defects in the baby/other poor pregnancy outcomes have produced mixed findings, with some finding possible links and others finding no links. However, the results of these studies may not be reliable. In general, medicines and other substances used by men around the time of conception are considered unlikely to adversely affect a pregnancy.

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 healthcare provider. They can access more detailed medical and scientific information from  

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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.

Disclaimer: This information is not intended to replace the individual care and advice of your health care provider. New information is continually becoming available. Whilst every effort will be made to ensure that this information is accurate and up to date at the time of publication, we cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes following decisions made on the basis of this information. We strongly advise that printouts should NOT be kept for any length of time, or for “future reference” as they can rapidly become out of date.

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