In our September 2009 enewsletter, we looked at findings from a Taiwanese study into the effects on an unborn child if its mother experiences epileptic seizures during pregnancy. The main risks found were prematurity and low birth weight and size, both of which can lead to other health problems.

Researchers at the Universidade Federal de São Paulo, in Brazil, have now been using animal models to explore the effect that exposure to seizures in the womb might have on a baby's development, in terms of movement (motor control) and mental processes.

The team first 'created' epilepsy models by breeding female rodents and inducing seizures in them using a chemical known as pilocarpine. They then measured the number of seizures each experienced over 60 days. At the end of this period, the researchers allowed the animals to mate and they then recorded their seizure frequency throughout pregnancy.

As soon as the offspring were born, the group examined the placentas of each mother for any signs of damage. Three months after birth the group evaluated various aspects of the offspring's behaviour and compared these to the behaviour seen in animals of the same breed and age, born to healthy, non-epileptic mothers.

The researchers noticed a decline in seizure frequency during pregnancy compared to that seen before pregnancy; however when they studied the epileptic mothers' placentas they saw distinctive areas of tissue death (caused by restricted blood flow). This indicates that the offspring were not receiving enough oxygen during pregnancy.

When the scientists observed the offspring's behaviour at three months, they noticed that they had a lower level of co-ordination and were less inclined to move around than their 'normal' counterparts. There were no differences between the two, however, in terms of the anxiety and depression-like behaviors examined.

These results suggest that exposure to seizures in the womb can lead to motor deficits in later life, possibly due to a lack of oxygen crossing the placenta. This emphasises the importance of good seizure control during pregnancy.

There are of, course risks, to unborn children of taking anti-epileptic drugs during pregnancy, and it is therefore vital that women who have epilepsy and are planning a pregnancy consult their neurologist to find the safest AED option for both mother and child.

You can help the ongoing research into AEDs and pregnancy, by joining the UK Epilepsy and Pregnancy Register.

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