register was set up in 1996 to try and overcome the lack of data
relating to the risks of major congenital malformations (MCMs) due to
exposure of the unborn child to anti-epilepsy drugs (AEDs) during
research has showed that women with epilepsy who did not take AEDs had
a slightly higher risk of having a baby with a malformation than women
without epilepsy. It was also known that taking a single AED in
pregnancy increased the risk of abnormalities in the baby, with sodium
valproate presenting the greatest risk. However, for women taking
certain combinations of AED at the same time, it was known that the
risk could be as high as 10 to 15 per cent.
researchers have conducted a large-scale study into the pregnancies of
over 3,600 women with epilepsy, whether they were taking AEDs or not,
looking specifically at MCMs in babies born to these mothers.
The new statistics available show:
96 per cent of live births born to women with epilepsy did not have a
major congenital malformation - only one child in 25 had a MCM
one AED makes the risk of having a baby with a major congenital
malformation 3.7 in 100, with carbamazepine carrying the lowest risk at
2.2 in 100 and taking sodium valproate raises the risk to 6.2 in 100
sodium valproate in daily dosages of over 1000mg is the greatest risk
when taking one AED and taking a daily dosage of lamotrigine above
200mg carries a similar risk to taking a daily dosage of up to 1000 mg
of sodium valproate. Taking lamotrigine at daily dosages of 200mg or
less does not increase the risk above 3.2 in 100
- Taking sodium valproate with any other AED carries a greater risk than any other combination of AEDs
two or more AEDs increases the risk to 6 in 100 and the combination of
lamotrigine and sodium valproate carries the highest risk of all. Any
combination which includes sodium valproate carries a two to three
times higher risk than any other combination of AEDs
Chief executive of the charity Epilepsy Action, Philip Lee, commented on the findings:
new piece of research is very important because it defines, more
clearly than previously, the risks to the unborn child associated with
different anti-epileptic drugs (AEDs) taken during pregnancy.
"For many years Epilepsy Action has been urging all women with epilepsy to seek pre-conception counselling. The
findings of this study show the importance of all women with epilepsy
discussing the options open to them with a health professional with an
expertise in epilepsy before planning a family. It is important to
stress that under no circumstances should women stop taking AEDs
without consulting their GP or epilepsy specialist, as this could be
potentially harmful to their health and that of their unborn child.
study will assist the clinician in providing more specific
pre-conceptual counselling for women with epilepsy and help clinicians
work with women to choose the most appropriate AED regime for them. The
best regime for an individual woman will aim to achieve good seizure
control for her and pose the minimum risk to her unborn child.
is important to note that the research shows that almost 96 per cent of
live births to women with epilepsy taking anti-epileptic drugs did not
have a major congenital malformation. This is lower than the 98-99 per
cent of live births to women in the general population that do not have
a MCM. The research shows that it should be possible to minimise the
risks of MCM to the babies of women taking AEDs by paying close
attention to the particular drugs and combinations prescribed."
Action also noted that previous information related to any congenital
abnormality whereas the new information from this study relates
specifically to major congenital malformations.