Newer epilepsy drug may also increase risk of birth defects
Publication Date:22/07/2008
Taking an epilepsy drug called topiramate while pregnant may increase the risk of birth defects, according to a new study. But the risk with topiramate doesn't appear to be any higher than the risk with other epilepsy drugs.
What do we know already?
If you're pregnant and have epilepsy, it's very important to continue taking your epilepsy medicine to prevent seizures. Having seizures can harm both you and your baby. But taking epilepsy drugs while pregnant does have risks. Studies on older epilepsy drugs have found an increased risk of birth defects, although most babies (more than 9 in 10) are born healthy.
Not much research has been done on the risks of birth defects with many newer epilepsy drugs. But now researchers have looked at the newer epilepsy drug topiramate. It is also sometimes used to prevent migraines.
What does the new study say?
The new study found that babies born to women who took topiramate while pregnant were more likely to have birth defects than is usual. The researchers gathered their data from the UK Epilepsy and Pregnancy Register, which follows the pregnancies and births of women with epilepsy.
Up to August 2007, the Register had recorded 178 babies born to women taking topiramate, either alone or with other epilepsy drugs. Of these, 16 babies (almost 9 percent) had major birth defects. This was higher than the normal rate (1 percent to 2 percent) but similar to the rate with other epilepsy drugs (4 percent to 9 percent).
Tell me more about the study's findings
Here are some figures from the study:
- Four babies (2.2 percent) had cleft lips or palates (this is when parts of the mouth don't grow together properly), which is 11 times higher than the usual rate.
- Of the 78 male babies, four (5.1 percent) had problems with their genitals, with two classified as major defects. This is 14 times higher than the usual rate.
However, many women were taking other epilepsy drugs in addition to topiramate, and these drugs probably had an effect on the risk of birth defects. When topiramate was taken with a drug called valproate, for example, the risk of major birth defects was highest.
But when researchers looked at the 70 babies born to women taking topiramate on its own, only three (around 4.5 percent) had major birth defects.
Where does the study come from?
The study was done by researchers in Ireland, Scotland and England, and was published in Neurology, which is the medical journal of the American Academy of Neurology. The study was paid for by the Epilepsy Research Foundation (a UK charity that funds epilepsy research) and also by several drug companies. Studies often receive funding from drug companies, and this doesn't necessarily affect the quality of their findings.
How reliable are the findings?
Only 178 women in the study took topiramate and, of these, only 70 women took topiramate alone. That's quite a small number and makes it hard to rely on the results. It would be useful to see figures for more women taking topiramate, so we know for sure that the increase in risk is not just down to chance.
Because so many women in the study were taking other epilepsy drugs in addition to topiramate, it's not possible to say which drug (or drugs) caused the increase in birth defects for these women.
Also, this type of study cannot prove for certain that babies got birth defects because their mothers took topiramate. It can show only that there might have been a link. This is because there could have been other things about these women, their pregnancies or their babies that caused the problem.
What does this mean for me?
The important thing is to find the safest way to treat women with epilepsy when they're pregnant. This study shows that topiramate, like other epilepsy medicines, may increase the risk of birth defects. This is an important finding, but we still don't know what drugs are safest to use.
If you're pregnant and have epilepsy, doctors think the most important thing is to take the drug that controls your seizures best. By controlling your seizures, you'll be helping yourself and your baby.
The study's findings are also useful for women who take topiramate to prevent migraines. Although the researchers didn't look at women with migraines, the higher risk of birth defects might apply to them as well. If you are pregnant or plan to get pregnant and are taking topiramate for migraines, talk to your doctor about whether another treatment might be best for you and your baby.
What should I do now?
If you have epilepsy and are thinking about getting pregnant, make sure you talk to your doctor. He or she may want to adjust your epilepsy drugs before you get pregnant. Some experts think it's best to take only one epilepsy drug during pregnancy. If you're taking more than one, you may want to talk to your doctor about this.
It may take a while to change your treatment and get it right. So it's a good idea to see your doctor several months (six if possible) before you plan to get pregnant. This will give you lots of time to get used to any new drugs and change them if they don't suit you.
If you are already pregnant, be sure to continue taking your epilepsy medicine and talk to your doctor about any questions or concerns. And remember, your chances of having a healthy baby are very good.
From:
Hunt S, Russell A, Smithson WH, et al. Topiramate in pregnancy: Preliminary experience from the UK Epilepsy and Pregnancy Register. Neurology. 2008: 71; 272-276.
To learn more, see our information on epilepsy.
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This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
