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As a newborn hospitalist, I am frequently called upon to counsel mothers on the risks and benefits of breastfeeding versus formula feeding their baby. Often this comes up in the context of concerns for potential harm to the newborn from medications that their mother is taking. Unfortunately, I don’t always have good data upon which to base a recommendation and the decision of whether or not to breastfeed can be quite challenging.

Pregnancy and epilepsy

Epilepsy is a common and potentially life-threatening condition diagnosed in over a million women of childbearing age in the United States, and it used to be designated as an absolute contraindication to pregnancy. Historically, pregnancy was known to increase seizure occurrence and to risk serious injury to mother and baby. Today, thanks to the development of safe and effective antiepileptic drugs (AEDs) and advances in obstetrical care, more than 24,000 babies are born each year to women with epilepsy.

There are, however, unique challenges facing women with epilepsy during pregnancy, particularly concerns of potential harm to the developing fetus from AEDs. Although uncommon, AED exposure can result in major congenital malformations, poor intrauterine growth, and long term developmental deficits. This has mostly been associated with the AED valproate, which is safe and effective in many patients and not just for epilepsy, but is now generally avoided in women who may become pregnant. In most cases, the benefit of AED use during pregnancy outweighs the risk and is safe when managed by a specialist with expertise in choosing the safest medication(s) and in appropriate monitoring of levels in the bloodstream.

Breastfeeding and epilepsy

Once a baby is born, the assessment of risk versus benefit when it comes to exposure to maternal medications necessarily changes. Because of concerning animal data showing neuronal injury from certain AEDs, and the known potential risk for neurodevelopmental problems in children born to mothers taking them, there has been disagreement over recommendations on breastfeeding. There just hasn’t been much in the way of data to base a decision on, and what we have involves very small numbers of babies. For many years, though, the standard recommendation has been slowly shifting towards comfort, particularly as newer AEDs have been rolled out, and a new study recently published in JAMA Neurology further supports their safety.

Previous studies have looked at levels of various AEDs in the breast milk. In this new study, researchers collected blood from 164 breastfed infants of mothers being treated for epilepsy between 5 and 20 weeks after birth. They found that in about half of the subjects, levels of AEDs in the blood were less that the lower limit of quantification. For most of the medications the mothers were taking, including the most commonly prescribed newer medications such as Keppra (levetiracetam), the majority of blood levels were found to be below the lower limit. Only one medications, lamotrigine, consistently had reliably detectable levels in the infant subjects.

So what does this mean? This study, which was the largest of its kind to date, shows that levels of AEDs in infants who are breastfed by mothers taking them are well below what they would have been exposed to for months in the womb. So taking into account the benefits of breastfeeding, the risk of exposure to AEDs through breast milk is low enough to have confidence in supporting a mother’s decision to do it.

Two quick caveats

There are two potential concerns that caregivers and medical professionals should be aware of when it comes to the babies born to mothers taking AEDs. Some of these medications interfere with the absorption of folate, thus increasing the risk of birth defects. In particular, inadequate maternal folate levels are associated with neural tube defects such as spina bifida and anencephaly. This is why since 1998 folate has been added to grain products in the United States, which has resulted in 35% fewer neural tube defects. Women taking AEDs should ensure that they are getting adequate folate intake, which may require taking a supplement in addition to a healthy diet.

The other potential health issue in breastfed infants born to mothers taking AEDs is vitamin D deficiency. Vitamin D deficiency is common, but even more so in women taking medications for epilepsy. Breast milk is also known to be low in the prohormone (it isn’t actually a vitamin since we make it ourselves with the help of sunlight), even when mothers are taking a supplement. Because of this, pediatricians and family docs have been recommending that young infants be given 400 IU, usually in the form of Vitamin D drops, every day until they are getting at least a liter of formula or adequate intake through solid food. I’ve seen rickets in a baby and it isn’t pretty.

Happy New Year!