(Date of issue: March 2016. 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 Public Health England 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?
Atenolol is a medicine that is prescribed to treat high blood pressure (hypertension), angina, and some forms of irregular heartbeat. It is also occasionally used in the prevention of migraine. Atenolol belongs to a family of medicines called beta-blockers.
Is it safe to take atenolol in pregnancy?
There is no yes or no answer to this question. When deciding whether to use atenolol during pregnancy it is important to weigh up how necessary atenolol is to your health against any possible risks to you or your baby, some of which might depend on how many weeks pregnant you are. Your doctor is the best person to help you decide what is right for you and your baby.
What is the recommended treatment for high blood pressure in pregnancy?
It is important to appropriately treat high blood pressure in pregnancy. Studies have shown that poorly controlled high blood pressure in pregnancy is linked to an increased risk of some birth defects, stillbirth, the baby growing more slowly than normal in the womb, and premature birth.
The National Institute for Health and Care Excellence (NICE) is a government body in the UK that produces guidelines for doctors. NICE recommends that women who have high blood pressure that started during pregnancy (sometimes called gestational hypertension or pregnancy-induced hypertension) are treated with labetalol wherever possible. Additionally, some women who were being treated for high blood pressure before pregnancy might be switched during pregnancy from their previous medicine to labetalol.
For some women who already had high blood pressure prior to being pregnant, continued treatment with atenolol in pregnancy might be considered to be the best option. Your doctor is the best person to help you decide what is right for you and your baby.
What if I have already taken atenolol during pregnancy?
If you have taken any medicines it is always a good idea to let your doctor know that you are pregnant so that you can decide together whether you still need the medicines that you are on and, if so, to make sure that you are taking the lowest dose that works.
Can taking atenolol 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.
A single study showed a higher than expected overall rate of birth defects in babies who had been exposed in the womb to atenolol. However, it is possible that this finding was due to problems with the way that the data in this study was collected and analysed. Further research is therefore needed to establish whether atenolol use in pregnancy increases the overall likelihood of birth defects in the baby.
Two studies have investigated whether hypospadias (where the opening of the penis is on the underside rather than at the tip) in male babies might be linked to exposure to atenolol in the womb. The results of these studies did not agree, with one finding a link and the other finding none. Poorly controlled high blood pressure in pregnancy has been linked to an increased risk of hypospadias in the baby. More research into birth defect rates in babies exposed to atenolol in early pregnancy is therefore required to determine whether use of atenolol in pregnancy can cause hypospadias or other birth defects.
Can taking atenolol in pregnancy cause miscarriage?
No studies have assessed miscarriage rates in women taking atenolol. Scientific research into this subject is therefore required.
Can taking atenolol in pregnancy cause stillbirth?
Poorly controlled high blood pressure in pregnancy is known to increase the likelihood of stillbirth. It is therefore complicated to work out whether medicines that are used to treat high blood pressure in pregnancy themselves increase the risk of stillbirth.
The occurrence of stillbirth has been analysed in a small number of women taking atenolol in pregnancy. Although, so far, the results have not been concerning, large scientific studies are required before we can say whether taking atenolol in pregnancy affects a woman’s risk of stillbirth.
Can taking atenolol in pregnancy cause preterm birth?
Women with poorly controlled high blood pressure in pregnancy are more likely to give birth early (preterm). Early delivery of the baby is sometimes medically induced because of the severity of the mother’s high blood pressure, or due to concerns about the baby’s health in the womb. Studies do not always provide information on whether early delivery was spontaneous or induced. It is therefore not always possible to work out whether medicines that are used to treat high blood pressure in pregnancy increase the risk of spontaneous preterm birth.
Seven studies have analysed the lengths of pregnancies in a total of around 450 women taking atenolol. Overall, the studies do not provide convincing evidence that taking atenolol in pregnancy leads to the baby being born earlier. However, the findings of the two studies that looked specifically at whether pre-term birth was more common in women who were treated with atenolol than in women treated with other high blood pressure medicines did not agree. More research is therefore required before we can say whether use of atenolol in pregnancy increases the risk of preterm birth.
Can taking atenolol in pregnancy cause my baby to be small at birth (low birth weight)?
Women with poorly controlled high blood pressure in pregnancy are more likely to have a low birth weight baby (weighing less than 2,500g). The effect of high blood pressure itself on a baby’s growth in the womb therefore needs to be considered when assessing whether medicines that are used to treat high blood pressure in pregnancy might further increase the risk of low birth weight.
Four studies have investigated the occurrence of having a baby who is smaller than expected for the stage of pregnancy in a total of around 300 pregnant women taking atenolol. All of these studies attempted to account for the underlying effect of the mother’s high blood pressure on growth of the baby in the womb. Two of the studies provided evidence that use of atenolol in pregnancy might be linked to reduced growth of the baby in the womb, with both showing that use of atenolol before 20 weeks of pregnancy was linked to the highest risk of having a smaller baby. More research is required to determine whether these effects are due to atenolol, the mother’s underlying illness, or a combination of the two.
Can taking atenolol in pregnancy cause other health problems in the baby/child?
Complications after birth
Side effects of beta-blockers include low heart rate, low blood sugar, and low blood pressure. Babies of women who are treated with beta-blockers around the time of delivery might therefore experience these symptoms for a few hours or days after birth. Some (but not all) studies have reported these symptoms in newborn babies exposed to atenolol in the womb. If you have taken atenolol in the weeks before delivery, your doctor or midwife might arrange for your baby to be born at a unit that can monitor and treat your baby if necessary.
Learning and behavioural problems in the child
A baby’s brain continues to develop right up 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 assessed whether atenolol use in pregnancy increases the risk of learning or behavioural problems in the child. This will ideally be the subject of future research.
Will I or my baby need extra monitoring during pregnancy or after delivery?
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. Using atenolol in pregnancy is not expected to cause problems that would require extra monitoring of your baby during pregnancy. However, women with high blood pressure are likely to be offered specialist care in addition to their normal midwife appointments during pregnancy, and to be more closely monitored to ensure that their blood pressure is in the correct range, and their baby is growing and developing as expected.
Women with high blood pressure in pregnancy are also advised to monitor themselves for symptoms of a severe form of high blood pressure called pre-eclampsia. If you are experiencing symptoms of pre-eclampsia you should seek urgent medical help. Symptoms of pre-eclampsia include:
• Severe headaches that often do not get better after using pain relief
• Visual problems, such as blurred vision, flashing lights, double vision, or floating spots
• Pain under the ribs, especially on the right-hand side
• Being sick
• Feeling breathless
• Sudden swelling of the face, hands, or feet
Babies born to women who used atenolol in late pregnancy might be closely monitored after birth to ensure that they are not experiencing adverse effects of beta-blocker exposure, such as low heart rate, low blood sugar, and low blood pressure. Babies experiencing these effects might require treatment and support for a few hours or days after delivery.
Are there any risks to my baby if the father has taken atenolol?
No studies have specifically investigated whether atenolol taken by the father can harm the baby through effects on the sperm, however most experts agree that this is very unlikely. More research on the effects of medicine use in men around the time of conception is needed.
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.
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.