Treatment of threadworms during pregnancy

(Date: January 2023. Version: 3.1)

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.

Quick read

Having threadworms in pregnancy does not harm the baby. Threadworms in pregnancy can be treated using hygiene measures, or with a medicine called mebendazole. Hygiene measures may be preferred in early pregnancy while the baby is developing.

What are threadworms?

Threadworms infect the bowel and cause itching of the anus (bottom). They are common in young children and spread very easily between household members. Threadworms during pregnancy can be unpleasant and might affect sleep due to itching but do not directly harm the baby.

How do I treat threadworms during pregnancy?

Pregnant women may be able to avoid taking medicines to treat threadworms by using strict hygiene measures to clear them. For details of these hygiene measures, please see the NHS information on Threadworms.

If hygiene measures do not clear up threadworms, or medicine use is preferred, mebendazole (Vermox®, Ovex®) can be used. There is no evidence that mebendazole harms the baby, and it is only absorbed into the body in small amounts. However, some women may prefer to try hygiene measures first and delay mebendazole treatment until the baby is fully developed at around 12 weeks of pregnancy.

Will my baby need extra monitoring?

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.

Having threadworms or taking mebendazole during pregnancy is not expected to cause any problems that would require extra monitoring of your baby.

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

We would not expect any increased risk to your baby if the father had threadworms or used mebendazole before or around the time your baby was conceived.

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

How can I help to improve drug safety information for pregnant women in the future?

Our online reporting system allows women with a current or previous pregnancy to create a digitally secure ‘my bumps record’. You will be asked to enter information about your health, whether or not you take any medicines, and your pregnancy outcome. You can update your details at any time during pregnancy or afterwards. This information will help us better understand how medicines affect the health of pregnant women and their babies. Please visit https://www.medicinesinpregnancy.org/Login/ to register.

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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

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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