Use of sildenafil in pregnancy

(Date: August 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 is it?

Sildenafil (often known as Viagra®) is used to treat erectile dysfunction in men. However, because it works by improving blood flow, it is also occasionally used in men and women to treat a condition where the pressure in the right side of the heart is too high (pulmonary arterial hypertension). A number of trials have also looked at whether sildenafil may be useful to improve blood flow in pregnancies where the baby has stopped growing (fetal growth restriction).

Is it safe to take sildenafil in pregnancy?

Relatively small numbers of women have taken sildenafil in pregnancy.

In 2018 a study looking at using sildenafil to treat pregnant women in whom the baby has stopped growing was halted early due to a number of babies having a problem after birth called  ‘persistent pulmonary hypertension of the newborn’ (PPHN). This is where the baby’s breathing system does not adapt to life outside the womb. This complication affected a small number of babies born to women taking sildenafil. Other studies have not made the same observation. However, as a precaution, it has been recommended that sildenafil is not currently used to treat fetal growth restriction.

Any woman who is taking sildenafil to treat pulmonary arterial hypertension and is planning a pregnancy should speak to her specialist pulmonary hypertension team to discuss her medication before she conceives. Pulmonary arterial hypertension can be very serious and can be difficult to manage during pregnancy. Continuing sildenafil during pregnancy may be necessary for some women. The doctors within your pulmonary hypertension team will be able to help you to weigh up any health benefits of sildenafil use against the possible risks to you or your baby.

This leaflet summarises the scientific studies relating to the effects of sildenafil on a baby in the womb.

What if I have already taken sildenafil during pregnancy?

If you have taken sildenafil in pregnancy it is important to let your doctor know; in particular you should inform the team looking after your pulmonary hypertension and your obstetrician. You should not make any changes to your medication without first speaking to your doctors.

Can taking sildenafil cause miscarriage?

No studies have assessed the chance of miscarriage in women taking sildenafil in early pregnancy.

Can taking sildenafil in pregnancy cause my baby to be born with birth defects?

A baby’s body and most internal organs are formed during the first 12 weeks of pregnancy. It is mainly during this time that some medicines are known to cause birth defects.

No studies have assessed the chance of birth defects in babies born to women taking sildenafil in early pregnancy and case reports describe a total of only seven pregnant women taking sildenafil. While none of their babies had birth defects, well-designed studies of much larger numbers of women are required to confirm that it does not cause birth defects.

Can taking sildenafil in pregnancy cause stillbirth?

Two studies that together include 103 pregnant women taking sildenafil do not suggest a link with stillbirth. However, many more pregnant women taking sildenafil need to be studied to confirm this finding.

Can taking sildenafil in pregnancy cause preterm birth or my baby to be small at birth (low birth weight)?

Studies of small numbers of pregnant women taking sildenafil do not currently suggest that this can cause preterm birth or low infant birth weight. These findings require confirmation with further research.

Can taking sildenafil in pregnancy cause learning or behavioural problems in the child?

A baby’s brain continues to develop until the end of pregnancy. It is therefore possible that taking certain medicines at any stage of pregnancy could have a lasting effect on a child’s learning or behaviour.

No studies have investigated learning and behaviour in children exposed to sildenafil in the womb.

Will I or my baby need extra monitoring during pregnancy?

Most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects as part of their routine antenatal care. If you have taken sildenafil in early pregnancy you may be offered additional and/or more detailed ultrasound scans as the potential effects of sildenafil use in early pregnancy are largely unknown.

Women who have used sildenafil in pregnancy may be advised to give birth at a hospital where there are facilities for monitoring and treatment of the newborn baby if problems develop.

Women with pulmonary arterial hypertension will be closely monitored during pregnancy, regardless of what medication they are using, to ensure that they remain well and that the baby is growing, moving, and developing as expected.

Are there any risks to my baby if the father has taken sildenafil?

We would not expect any increased risk to your baby if the father took sildenafil 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 healthcare providers; in particular the pulmonary hypertension team, your obstetrician, or GP. 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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