by Dr. David Burkholder, Mayo Clinic
Women with epilepsy (WWE) who are child-bearing age represent a special at-risk population. Potential harm to the child and risk of seizures to mother can create difficulty when managing epilepsy during pregnancy. With appropriate planning, though, these risks can be reduced to help ensure the safety of both baby and mother.
RISK TO UNBORN CHILD
Many medications we use to manage epilepsy are potentially harmful to the unborn child. About 1-2% of the general population may give birth to a child with a major fetal malformation such as cardiac abnormalities, cleft lip and palate, or problems with the formation of the nervous system. Studies show that children born to mothers taking antiseizure medications do have an increased risk of these conditions, and overall these rates are probably around 3-6%. However, we know that some AEDs (antiepileptic drugs) are more harmful than others. Valproate specifically has a higher rate of any of these complications, on average about 10%, with a higher risk for women on higher doses. Children exposed to valproate before birth have also been shown to have worse development, such as lower IQ, compared to children exposed to other AEDs. For these reasons, valproate is not recommended for first-line treatment of epilepsy in women of child-bearing age. Phenobarbital and topiramate may also be associated with higher complication rates. Conversely, levetiracetam and lamotrigine are considered two of the safest AEDs to use during pregnancy with much lower rates of complication. Use of folic acid may help prevent some of these complications, and may also help combat the developmental effects seen with valproate. WWE are also encouraged to enroll in the North American AED Pregnancy Registry if they become pregnant while being treated for epilepsy to help us better understand the risks associated with AED use during pregnancy (see link at end of blog entry).
RISK OF SEIZURES
While the majority of WWE will not have changes in seizure frequency during pregnancy, as many as approximately one-third of women may have more seizures than usual. Additionally, how the body processes and clears AEDs can change with pregnancy. Two medications in particular, lamotrigine and oxcarbazepine, can have lower-than-usual levels in the blood as the body clears them out much faster during pregnancy. Because of these factors, close follow up with a neurologist and monitoring of drug levels are important.
In order to reduce these risks as much as possible, there are several special considerations that are important when it comes to pregnancy in women with epilepsy:
Let your neurologist know ahead of time when you are interested in becoming pregnant
Establish effective therapy before becoming pregnant, 9-12 months beforehand if possible, including reducing or eliminating the most harmful AEDs (like valproate)
Establish your baseline drug levels at your ideal doses
Take folic acid 0.4-4 mg daily
Follow up regularly with your neurologist and obstetrician
Drug levels are recommended on about a monthly basis
Your neurologist may adjust your AEDs if levels are lower than your established baseline, even if you are not having seizures
If your AEDs were adjusted upward during pregnancy, they can be reduced to their pre-pregnancy doses shortly after your child is born over a period of weeks to the first few months depending on your neurologists clinical judgement
Breast-feeding is a special consideration. While not technically part of pregnancy, it is obviously an important part of life starting immediately after birth. In the past, WWE were discouraged from breast-feeding out of concern that exposure to AEDs through the breast milk could hurt development of the child. Recent studies looking at groups of children born to WWE who were breastfed have not shown any adverse outcomes compared to children who were not breastfed. Two studies specifically looking at children exposed to carbamazepine, lamotrigine, valproate, and phenytoin in breast milk also did not find any adverse effects. Since no clear risk has been identified, and there are benefits linked to breast-feeding, it is current practice to encourage breast-feeding if desired by the family.
The most important thing to remember is that the vast majority of WWE will have healthy babies!