Risks of taking anti-epileptic drugs in pregnancy

Most women with epilepsy have healthy pregnancies and give birth to healthy babies. However, there are some risks related to taking anti-epileptic drugs (AEDs) in pregnancy. Women with epilepsy are advised to talk to their epilepsy specialist about the risks, and how to minimise them, before they get pregnant.  

There is a small risk that a baby born to a mother without epilepsy will have a malformation, (for example a hole in the heart, damaged spine, unseparated fingers, or wide set eyes).  The risk of having a baby with a malformation is slightly higher if you have epilepsy or take anti-epileptic drugs (AEDs). 

The exact risk of having a baby with a malformation depends on a number of things.  This includes which AED you take and how many AEDs you take, during the first three months of pregnancy. This is why - if possible- it is advisable to ask your doctor to review your treatment before you get pregnant. 

The UK Epilepsy and Pregnancy Register

The UK Epilepsy and Pregnancy Register, was set up to find out more about the risks of having epilepsy and taking anti-epileptic drugs during pregnancy.  Women with epilepsy can join the UK Epilepsy and Pregnancy Register.

The UK Epilepsy and Pregnancy Register published a report in September 2005. This gave the results from a study of 3,607 women with epilepsy who joined the register at the start of their pregnancy. This included women who were taking anti-epileptic drugs (AEDs) and women who were not taking AEDs.  The information on major congenital malformations, that follows, is from this report. It is the most complete information available. 

Major congenital malformations (MCMs)

Some of the problems that may occur in babies who are born to mothers with epilepsy, are called major congenital malformations (MCMs).

Congenital means a condition that a baby is born with. MCMs include malformations of the spinal cord and spine (spina bifida), the heart (such as hole in the heart), the ribs, the bladder, the sexual organs and the fingers and toes (such as unseparated fingers). Babies born with MCMs may need surgery after their birth.

The risk of having a baby with MCMs, is related to the mother having epilepsy, and to any anti-epileptic drugs (AEDs) she takes during pregnancy.

• One to two children in every 100 born to women in the general population have MCMs (actual 1 to 2 per cent)
• Three to four children in every 100 born to women with epilepsy who take one AED (known as monotherapy) have MCMs (actual 3.7 per cent)  
• Six children in every 100 born to women with epilepsy who take two or more AEDs (known as polytherapy) have MCMs (actual 6 per cent).

Risks of major congenital malformations (MCMs) related to specific anti-epileptic drugs (AEDs)

• Carbamazepine taken as a single drug treatment (known as monotherapy) carries the lowest risk. Around two babies are born with MCMs in 100 pregnancies in women taking the drug (actual 2.2 per cent)
• Taking lamotrigine as monotherapy carries a risk of around three babies in 100 (actual 3.2 per cent)
• Taking sodium valproate as monotherapy at a daily dosage under 1000mg, carries a risk of around five babies in 100 (actual 5.1 per cent)
• Taking sodium valproate as monotherapy at daily doses over 1000mg carries a risk of around nine babies in 100 (actual 9.1 per cent)
• Taking sodium valproate together with another AED, increases the risk of an unborn baby having MCMs.
• Taking carbamazepine and sodium valproate together carries a risk of around nine babies in 100 (actual 8.8 per cent)
• Taking sodium valproate and lamotrigine together carries a risk of around 10 babies in 100 (actual 9.6 per cent)
• The information from the study did not give any real information on vigabatrin, gabapentin, topiramate, tiagabine, oxcarbazepine, levetiracetam and pregabalin. For information on these AEDs you could speak to your doctor, or speak to an advisor at the UK Epilepsy and Pregnancy Register on 0800 389 1248.

Minor malformations

Babies born to mothers who have epilepsy also have a slightly higher risk of having minor malformations. Minor malformations do not necessarily require medical treatment and may not be permanent.  Examples of minor malformations include small fingers and toes with small nails, facial features such as wide set eyes, low set ears and short neck. At the time of writing, the exact risk of minor malformations in babies born to mothers who take anti-epileptic drugs (AEDs) is unknown. 

Neurodevelopment

Neurodevelopment is a term used to describe the development of a range of skills.   Examples of neurodevelopment skills include motor skills (for example how well we can use our hands and fingers), communication skills and behaviour.  
It is not yet clear whether babies born to mothers with epilepsy or taking anti-epileptic drugs (AEDs), have a higher risk of neurodevelopment problems.  Two recent studies suggested that taking sodium valproate in pregnancy, may increase the risk of children having autism and a lower IQ score. 

Although, the lower IQ score was within the normal range, the researchers will continue to watch the development of these children.  They will tell us whether these children ‘catch-up’ with other children as they grow older, or whether they fall further behind.

However, more research will become available in the next few years. 

What does this information about malformations and neurodevelopment tell us?

This information tells us that the majority of women with epilepsy give birth to healthy babies.  It also tells us that

• Taking one anti-epileptic drug (AED)(known as monotherapy) in pregnancy is linked to a lower risk of malformations in a baby.
• Taking two or more AEDs (known as polytherapy) in pregnancy increases the risk of malformations in a baby.
• Sodium valproate appears to carry a higher risk of malformations and neurodevelopment problems in an unborn child. 

Our advice to you

Very few mothers with epilepsy will have a baby with a major congenital malformation (MCM). But it really is worth talking to your doctor about pregnancy and epilepsy. 

Your doctor may be able to make changes to your anti-epileptic drugs (AEDs) before you get pregnant. This is to lower the risk of malformations in an unborn baby, when you do get pregnant. 

During your pregnancy, it is very important to continue taking your anti-epileptic drugs (AEDs) as usual. If you stop taking your AEDs during pregnancy, your seizures may become worse. This can seriously affect the health of you and your unborn baby. In severe cases the mother or baby may die.

Also, by the time you notice you have missed your period, your baby has already started to develop its major organs. So, if you stop taking your AEDs during pregnancy, you won’t necessarily reduce the risk of malformations in your unborn baby.
After your child is born, you will get a child development record (red book) for you to use to measure your child’s development.  If you become worried that your child is not developing normally, speak to your doctor. Your doctor may ask a specialist to see your child. The specialist will arrange for your child to have therapy if necessary (for example speech therapy or social communication therapy).
If you would like to talk about these risks, you could speak to your doctor or contact the Epilepsy Helpline, freephone 0808 800 5050.