Pregnancy and Epilepsy

December 14, 2007

Pregnancy is a very strange phenomenon in that it has it's own disease processes that can mimic diseases seen in the non-pregnant state.  But although both pregnancy and epilepsy can cause seizures, seizures in pregnancy are usually associated with pregnancy-induced hypertension (PIH, pre-eclampsia), so there are other signs and symptoms to tip off the obstetrician that a seizure is not the epilepsy of the non-pregnant variety.

Epilepsy is serious business, and people still die from it, either from the seizure itself or because of having a seizure in the wrong place or at the wrong time. 

Pregnancy Terms Defined

Eclampsia is the old word meant to describe a seizure associated with pregnancy in which there is brain-swelling as a result of pregnancy-induced hypertension. In fact, "pre-eclampsia," the previous word for the disease that was replaced by "pregnancy-induced hypertension," is a pessimistic label, as if it were expected to progress to eclampsia.

As stated above, seizures due to PIH in  pregnancy are easily able to be differentiated from seizures of epilepsy, and the pregnancy-caused "eclamptic" seizures are more dangerous.  But a patient with epilepsy is still considered high risk, because epilepsy itself is high risk for the mother, and anything that can hurt the mother hurts the life support for the baby.  In the USA there are two to three million epilepsy patients, so it can commonly be seen in pregnancy.

If morning sickness interferes with the proper pill-taking, this can lead to a worsening of the epilepsy. But otherwise pregnancy seems to have little effect on the epilepsy if the epilepsy is well controlled. It's only when the epilepsy is poorly controlled that the extra burden of pregnancy can make the seizures worse or more frequent.

Making Epilepsy Safe For The Baby

With a well controlled epilepsy in pregnancy, the major concern, then, is whether the medicines used to control the epilepsy are safe for the developing baby.  The goal of therapy of epilepsy during pregnancy, like the goal of any therapy during pregnancy, is to use the least amount of medicine that will still control the seizures.  In this respect, it becomes a risk vs. benefit issue in evaluating the epilepsy medication.

In my practice, the most commonly drugs used are Depakote (Valproic Acid), Dilantin(diphenylhydantoin), phenobarbital, and magnesium sulfate.  Magnesium sulfate differs from the rest in that it's the only agent that is a B category, which poses no undue risk to the fetus.  But magnesium sulfate is used in acute situations, via IV.  Valproic acid is associated with brain and spinal problems, but even so the risk is less than 10%.

Phenobarbital is an old drug (since 1912) which used to be used fairly liberally in pregnancy to treat "mild" pre-eclampsia, if there is such a thing.  Studies on abnormal development in babies exposed to phenobarbital have been inconclusive in that it isn't clear whether the increase in the minor defects (cleft lip, etc.) are a result of the phenobarbital or of the disease of epilepsy itself or a combination of the two.  A definite problem with phenobarbital is that, being a barbiturate, it is addictive, and babies so exposed, once born and cut off from it, may have withdrawal.  They may also experience bleeding problems, since phenobarbital may interfere with the newborn's Vitamin K, necessary for health clotting ability.

Dilantin, which is related to phenytoin and phenytoin for that matter is associated with a well-recognized Fetal Hydantoin Syndrome (FHS), which includes abnormalities of the skull, face, and limbs.

I have to emphasize that as scary as all of this sounds, still the risk of major problems is less than the disastrous outcome of epilepsy gone untreated.  Risk to babies exposed to these necessary drugs is three to four times higher than the general population, but that may translate to anywhere from 2% to 30%, depending on the agent used.  A Maternal-Fetal Medicine consult by a perinatologist can give the odds to a particular situation as well as perform a Level III ultrasound to look the babyover thoroughly for any tell-tale signs of abnormal development.

These drugs may just have to be a necessary evil until newer drugs come along that can move the FDA-assigned risk up the alphabet into A or B categories.  Until that time, the nature of epilepsy is such that treatment with what we have is  mandatory.  Otherwise, a baby has no chance at all if the epilepsy creates the worst scenarios for the expectant mother.

 

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