Chapter 1: Epilepsy and Pregnancy

INTRODUCTION

Epilepsy is defined by the recurrence of unprovoked seizures, with seizures being defined as recurrent episodes of abnormal, excessive excitation and synchronization of a population of cortical neurons that disturbs brain function with resulting changes in attention and/or behavior. Epilepsy is generally thought of as grand mal convulsions, but is, in fact, a number of syndromes and diseases that have many different manifestations and causes. Epilepsy or its treatment has the potential to interfere with sexual and reproductive health in many ways. Seizures can affect neuroendocrine function, and hormones can affect seizure occurrence. The treatment typically consists of daily, long-term antiepileptic drug (AED) regimens. However, as epilepsy is not a single-disease entity, the optimal treatment regimen can vary substantially among individuals. The treatment of epilepsy affects women across the life span: appearance, menstrual cycle, contraception, fertility pregnancy, and menopause.

There are approximately one-half million women with epilepsy (WWE) of childbearing age in the United States, translating to approximately 25,000 births per year.¹ In the United States alone, a WWE has a baby about every 20 minutes. Epilepsy is the second most common neurologic diagnosis encountered in pregnancy (headache is the most common) and it is thus important for obstetricians, neurologists, and primary care providers to understand the interactions between pregnancy and epilepsy.

CLINICAL PRESENTATION

Although the majority of WWE will have been diagnosed before becoming pregnant, population studies suggest that 40% to 45% of WWE will not be initially diagnosed until the age of 20 to 25 years or older.^2,3 Because the majority of women of reproductive age are not pregnant at any given time, most initial diagnoses of epilepsy in women of reproductive age will be established outside of pregnancy. Nonetheless, given the relative frequency of both new-onset epilepsy and pregnancy in women of reproductive age, the initial diagnosis of epilepsy will sometimes be made during pregnancy.

The diagnosis of epilepsy can be challenging. In fact, most reports of epilepsy in pregnancy either rely on the patient’s reported diagnosis or do not specify how the diagnosis was established.

DIAGNOSIS

The initial diagnosis of epilepsy may be straightforward but frequently is not. It requires a description of the events by one or more eyewitnesses and the interpretation of this history by a qualified provider. The initial step is the determination of whether a neurologic event was actually an epileptic seizure, as a number of conditions may be incorrectly diagnosed as a seizure (Table 1-1). There is substantial opportunity for variation in interobserver interpretation, and the interpretation of these events by the treating physician plays an important role.