Approximately 0.2-0.7 percent of pregnant women world-wide have epilepsy, making it the most common major neurological complication of pregnancy. Caring for the welfare of both the woman and her developing baby is highly skilled, as seizures must be controlled as well as possible, without causing harm to the child.

In our August enewsletter, we focused on the effects of exposure to anti-epileptic drugs (AEDs) in the womb. However, this recent study looks at pregnancy and epilepsy from a different angle; examining the actual risk to the unborn child if its mother experiences seizures.

Previous studies of this nature have reported links between epilepsy and adverse effects to the baby, but others have found little or no association. In the current project, researchers from Tai Pei Medical University, in Taiwan, hoped to clear some of the confusion.

The team used the Taiwan National Health Insurance Research Data set, to collect and analyse records from 1,016 women with epilepsy, who gave birth to single children between 2001 and 2003. All of the women had been diagnosed with epilepsy within two years prior to delivery.

The group was divided into those who had experienced seizures during pregnancy (503) and those who had not (516). Please note that women with seizures during pregnancy were defined as those who were hospitalized or treated in the emergency department for epilepsy during pregnancy. This means that the seizures they had were relatively severe.

Records from 8,128 women of the same age who gave birth during these years, but did not have epilepsy or any other chronic disease, were also examined for comparison. This group served as a control.

The results showed that, compared to women without epilepsy, women who had seizures during pregnancy were 36% more likely to have a low-birth-weight baby (weighing less than 2,500 grams). They were also 63% more likely to give birth prematurely (before 37 weeks), and 37% more likely to have a baby who was small for its gestational age, i.e. with a birth weight below the 10th percentile for its age at delivery.

Percentile charts are used by doctors to monitor the weight and growth of babies and chidren, to ensure that they are developing normally for their age. They are standard ranges based on thousands of growth sudies. If a 5 yr old boy has a height in the 60th percentile for his age, it means that 60% of boys of the same age will be shorter or of equal height to him, and 40% will be taller. For a baby whose birth weight is in the 10th percentile, 10% of other babies of the same sex, born at the same no. weeks, will weigh the same or less than this and 90% will weigh more.

In addition, women who experienced seizures during their pregnancy had a 34% greater risk of having a baby that was small for gestational age, compared those who had epilepsy but did not have seizures.

Overall, the women who had epilepsy but were free of seizures during pregnancy, had very little increased risk of premature delivery and low birth weight / size than those in the control group. However, the group who experienced seizures whilst pregnant had a significantly greater chance of these outcomes.

These results suggest that it is the seizures themselves in pregnant women with epilepsy that contribute greatly to the risk of premature delivery and low birth size / weight.

There are several possible explanations for the link between seizures and adverse pregnancy outcomes. Trauma caused by a woman's seizures could rupture the membranes that surround the baby in the womb, increasing the risk of infection and early delivery. Injury to the child may also result from contractions in the womb that occur during seizures.

More research is needed into precisely how seizures interfere with the baby's development; but low birth weight / size and prematurity can predispose babies to infection and other health problems. This study highlights the importance of seizure control during pregnancy, and makes a case for proper interventions by professionals to prevent seizures occurring. These could include helping women control seizures for a period of time before pregnancy, helping them to sleep better, providing education about the risks of seizures while pregnant and teaching improved strategies for coping with stress.

Read more here