(Date of issue: February 2016. Version: 1.3)
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?
Venlafaxine (Efexor XL®, Alventa XL®, Bonilux XL®, Depefex XL®, Foraven XL®, Politid XL®, Ranfaxine XL®, Tifaxin XL®, Venaxx XL®, Vensir XL®, Winfex XL®) is a medicine used to treat depression and generalised anxiety disorder. Venlafaxine belongs to a family of medicines called serotonin and noradrenaline reuptake inhibitors (SNRIs) and works in a similar way to selective serotonin reuptake inhibitor antidepressants (SSRIs).
Is it ‘safe’ to take venlafaxine in pregnancy?
There is no ‘yes’ or ‘no’ answer to this question. When deciding whether or not to take venlafaxine during pregnancy it is important to weigh up how necessary venlafaxine is to your health, against the possible risks to you or your baby, some of which will depend on how many weeks pregnant you are. Remaining well is particularly important during pregnancy and while caring for a baby. For some women, treatment with venlafaxine in pregnancy may be necessary.
This leaflet summarises the scientific studies relating to the effects of venlafaxine on a baby in the womb. It is advisable to consider this information before taking venlafaxine if you are pregnant. Your doctor is the best person to help you decide what is right for you and your baby.
What if I have already taken venlafaxine during pregnancy?
If you have taken or are taking 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 and only for as long as you need to.
It is very important that you do not suddenly stop taking venlafaxine as this could be dangerous to you, and therefore to your unborn baby if you are pregnant. Do not make any change to your medication without first talking to your doctor.
Can taking venlafaxine in pregnancy cause birth defects in the baby?
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.
Over 3,000 pregnant women taking venlafaxine have been studied. In these studies women who took venlafaxine in early pregnancy were no more likely to have a baby with a birth defect than women who didn’t. These studies are designed to investigate whether a medicine can commonly cause birth defects. However, they may not show if a medicine increases the chance of a particular type of birth defect.
One study which was designed to look for possible links between venlafaxine use in pregnancy and specific birth defects has been published in a scientific journal. A possible link between venlafaxine use in early pregnancy and heart defects in the baby was identified. Venlafaxine is similar to a group of antidepressants called selective serotonin reuptake inhibitors (SSRIs). Many studies have been done to investigate whether use of SSRIs in the first trimester of pregnancy might slightly increase the chance of the baby having a heart defect. These studies have produced mixed results. A link between venlafaxine or SSRI use in pregnancy and heart defects in the baby has therefore not been confirmed.
One study also showed possible links with cleft palate, limb defects, gastroschisis (where part of the baby’s bowel protrudes outside of the body through a hole next to the tummy button), and hypospadias (where the opening of the penis is on the underside instead of at the tip). Because these results were from a single study, further research is needed to assess whether taking venlafaxine in pregnancy might increase the chance of certain specific birth defects in the baby.
Can taking venlafaxine in pregnancy cause miscarriage?
It is currently unclear whether taking venlafaxine in pregnancy increases the chance of miscarriage. Three small studies that compared miscarriage rates between women taking venlafaxine and women not taking this medicine suggested that miscarriage may be more common in women taking venlafaxine, although a fourth study did not agree with this finding. None of these studies used the most up to date statistical methods that take into account other factors that are linked to miscarriage and more research into this subject is therefore required.
Can taking venlafaxine in pregnancy cause preterm birth or my baby to be small at birth (low birth weight)?
The three studies that have assessed whether women taking venlafaxine are more likely to give birth earlier have not provided clear proof that this is the case.
The only small study to assess whether venlafaxine use in pregnancy affects the baby’s birth weight found no evidence that it did.
More research is however required to confirm these findings.
Can taking venlafaxine in pregnancy cause stillbirth?
A single study that assessed whether stillbirth occurred more commonly in a group of women taking venlafaxine or related medicines provided no strong proof that this is the case. Further research on groups of women specifically taking venlafaxine is required before we can say whether or not use in pregnancy increases the risk of stillbirth.
Can taking venlafaxine in pregnancy cause other health problems in the child?
Withdrawal symptoms at birth (‘neonatal withdrawal’)
Withdrawal symptoms are thought to occur as a result of the newborn baby’s body having to adapt to suddenly no longer getting certain types of medicines through the placenta. Studies have shown that babies who were exposed to medicines related to venlafaxine in the womb can suffer from neonatal withdrawal. There are a number of case reports of babies exposed to venlafaxine in late pregnancy who showed symptoms of neonatal withdrawal after delivery. Close monitoring of your baby for a few days after birth may therefore be advised if you have taken venlafaxine regularly in the weeks before delivery.
Persistent Pulmonary Hypertension of the Newborn (PPHN)
PPHN or ‘persistent pulmonary hypertension of the newborn’ occurs when a newborn baby’s lungs do not adapt to breathing outside the womb. PPHN generally only affects around 1 or 2 out of every 1,000 newborn babies but can be serious.
Some studies show that PPHN is more common in babies of women who took an SSRI in pregnancy. Because venlafaxine is chemically related to SSRIs, there is therefore a theoretical risk that venlafaxine use in pregnancy might also increase the risk of PPHN in the baby.
There is currently very little information on whether use of venlafaxine in pregnancy increases the risk of PPHN in the baby. The only study to investigate this was very small and did not have enough women taking venlafaxine in pregnancy to be certain that the risk of PPHN is not increased.
Learning and behavioural problems
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.
A single study has provided no proof that use of venlafaxine in pregnancy affects a child’s intelligence or behavior. More studies into the rates of behavioural and learning problems in children exposed to venlafaxine in the womb are required before we can say whether there may be any effects.
Will my baby need extra monitoring during pregnancy?
As part of their routine antenatal care, most women will be offered blood tests and scans from around 11 weeks of pregnancy, and a further scan at around 20 weeks to screen for birth defects in the baby. Taking venlafaxine in pregnancy would not normally require extra monitoring of your baby.
Are there any risks to my baby if the father has taken venlafaxine?
We would not expect any increased risk to your baby if its father took venlafaxine before, or at 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.
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.