Pregnancy and epilepsy; meeting the challenges over the last 25 years: The rise of the pregnancy registries

Current safety concerns about the use of antiseizure medications in pregnancy

INTRODUCTION

Given the high prevalence of epilepsy in women of childbearing potential (15 million out of 50 million people worldwide), antiseizure medication (ASM) use in pregnancy is common. Identifying the safest and most effective ASM to use during pregnancy is often difficult, but also crucially important. The challenge is to balance two needs: maintaining seizure control while minimizing teratogenicity.

AREAS COVERED

This review looks at seizure- and treatment-related risks to mother and fetus during pregnancy, existing healthcare information programmes, strengths and pitfalls of the main pregnancy registries, known and supposed pharmacokinetic changes during gestation, the utility of therapeutic drug monitoring, and safety concerns. Articles and related content were screened on available publications after January 2000.

EXPERT OPINION

The use of newer ASMs during pregnancy is still limited, as shown by the paucity of data collected by different pregnancy registries. Choosing these medications can be challenging, partly due to unknown pharmacokinetic modifications in pregnancy, an aspect that serum drug monitoring might help to clarify. The safest treatment is chosen also taking into account the woman's needs, concerns and wishes, but adequate pre-pregnancy counseling is necessary to properly inform her about personal and fetal risks related both to seizures and to medications.

Preventing Teratogenicity in Women with Epilepsy

Over the last 50 years there has been a significant increase in our understanding of the issues faced by women with epilepsy, in both planning and undertaking pregnancy. The risks of teratogenicity associated with antiseizure medications have emerged slowly. The major pregnancy registers have substantially contributed to our knowledge about teratogenic risk associated with the commonly used antiseizure medications. However, there are substantial gaps in our knowledge about the potential risks associated with many third-generation drugs. The remit of the pregnancy registers and the wider research focus has moved beyond anatomical major congenital malformations. Increasingly neurodevelopmental and behavioral abnormalities have been investigated after in utero exposure to antiseizure medications. Public health approaches can help reduce the risk of teratogenicity. However, neurologists still have a vital role in reducing the risk of teratogenicity at an individual level for women attending their clinic. They also have responsibility to ensure that women with epilepsy are aware of the rationale for the different available options.

Prescribing Trends for Valproate Among Pregnant Women: A Cross-sectional Study in 2013 and 2016 Using the French Health Insurance Database

OBJECTIVE

We aimed to describe the prescribing trends for sodium valproate (VPA) and alternative drugs during and around pregnancy, comparing 2016 (after the recommendations on valproate for women were reinforced by the EMA) to 2013 (before the recommendations).

METHODS

Using the French National Health Insurance Database, a cross-sectional study was carried out in 2013 and in 2016, including women who became pregnant and had at least one reimbursement claim for VPA in the two years prior to pregnancy or during pregnancy. Exposure to VPA and its alternatives was then measured for each quarter, in the two years before pregnancy (pre-conception), during pregnancy and in the year after pregnancy (post-partum).

RESULTS

Among pregnant women with epilepsy (N=2,607 pregnancies), the proportion exposed to VPA during pregnancy decreased from 26.4% to 9.3% between 2013 and 2016, alongside an increase in lamotrigine and levetiracetam use. Among pregnant women with bipolar disorder (N=4,278 pregnancies), the proportion of women exposed during pregnancy decreased from 3.7% in 2013 to 1.9% in 2016, without any switch to alternative drugs. In both populations, less than one third had consulted a specialist before pregnancy.

CONCLUSION

As recommended by the EMA, a change in practice over the period 2013-2016 was observed, with fewer women exposed to VPA during pregnancy and before pregnancy. However, in 2016, a large number of women were exposed to VPA in the first trimester of pregnancy (N=471), which could suggest that the timing of pregnancy should be better planned whenever possible.

Epilepsy in Pregnancy—Management Principles and Focus on Valproate

An estimated 60 million people worldwide suffer from epilepsy, half of whom are women. About one-third of women with epilepsy are of childbearing age. The childbirth rate in women with epilepsy is about 20–40% lower compared to that of the general population, which may be partly due to a lower number of these women being in relationships. Lower fertility in women with epilepsy may be linked to the disease itself, but it is mainly a result of the treatment provided. Valproate, as an antiepileptic drug inhibiting histone deacetylases, may affect the expression of genes associated with cell cycle control and cellular differentiation. Evidently, this drug is associated with the risk of malformations although other antiepileptic drugs (AEDs) may also trigger birth defects, however, to a lower degree. Valproate (and to a certain degree other AEDs) may induce autism spectrum disorders and attention deficit hyperactivity disorder. The main mechanism responsible for all negative effects of prenatal exposure to valproate seems inhibition of histone deacetylases. Animal studies show a reduction in the expression of genes involved in social behavior and an increase in hippocampal cytokines. Valproate-induced oxidative stress may also contribute to neural tube defects. Interestingly, paternal exposure to this AED in mice may trigger neurodevelopmental disorders as well although a population-based cohort study does not confirm this effect. To lower the risk of congenital malformations and neurodevelopmental disorders, a single AED at the optimal dose and supplementation with folic acid is recommended. VPA should be avoided in women of childbearing age and especially during pregnancy.

Two cases of focal status epilepticus in pregnancy

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Two pregnant women with a history of epilepsy were found in focal status epilepticus.

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VEEG and fetal heart tracing were examined simultaneously with the patient’s seizures.

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The patient in Case 1 was treated more conservatively than Case 2 despite similar findings on FHT.

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Case 1 eventually stopped seizing while Case 2 developed complications related to ASM treatment.

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How can we incorporate FHT during the management of pregnant women with seizures?

The management of women with epilepsy (WWE) presents many challenges for physicians. The primary goal during pregnancy is to achieve the best possible control of seizures with the least adverse effects associated with exposure to antiseizure medications (ASMs). Even though the guidelines for managing pregnant WWE are expanding, no definitive guidelines exist for the treatment of status epilepticus (SE). Additionally, much of our data comes from the effect of generalized tonic clonic seizures on the fetus. There is very little data on the effect of focal seizures and even less on focal SE. Here we present two cases of pregnant WWE who presented in focal SE, who underwent simultaneous video-EEG monitoring and fetal heart tracing (FHT). During each focal seizure the FHT demonstrated a normal baseline heart rate with moderate variability. In the second case due to continuous seizures more aggressive treatment had to be started. This led to maternal relative autonomic instability as well as absent variability on FHT. These findings raise many questions on the management of focal SE during pregnancy including if the effect of treatment is worse than the seizures, and how do we balance our goals for both mother and fetus?

Risk factors of fetal deaths and major birth defects in newborns of women with epilepsy: An Egyptian prospective study

OBJECTIVES

Pregnancy registries for women with epilepsy (WWE) are arising all over the world. The aim of this work was to assess the risk factors of pregnancy losses and major birth defects (MBDs) of WWE through the Egyptian Registry of Anti-seizure medications and Pregnancy system.

METHODS

An observational prospective study was conducted over 24 months (2018-2020). The following data were assessed: seizure control during pregnancy, Anti-seizure medications (ASMs) regimen, folic acid supplementation, and birth outcome.

RESULTS

This study included 211 pregnant WWE, with mean age of 27.30 ± 5.51 years. One hundred eighty-six (89.9%) patients were on ASMs, from which 110 (59.1%) patients were on monotherapy. One hundred sixty-nine (80.0%) had healthy living babies, while fetal deaths occurred in 27 patients (12.8%) (25 abortions and 2 stillbirth), two patients (1%) had neonatal deaths, while 13 patients (6.2%) had living babies with MBDs. Although taking folic acid in the first trimester was a protective of fetal deaths (RR < 1, P 0.011), it was not a protective of MBDs. Seizure freedom during the entire pregnancy regardless of seizure type was another protective factor against fetal deaths (RR < 1, P < 0.001). Polytherapy exposure significantly increased the risk of MBDs compared with monotherapies (RR > 1, P 0.014). History of previous MBD was another risk factor of MBDs (RR > 1, P 0.027).

CONCLUSION

History of previous MBD and polytherapy exposure increased the risk of MBDs. Taking folic acid during first trimester and being seizure free during pregnancy were protective factors against fetal deaths.

Zonisamide safety in pregnancy: Data from the UK and Ireland epilepsy and pregnancy register

BACKGROUND

Animal data suggest teratogenic effects with zonisamide use and risk of pregnancy losses. Human data following zonisamide exposure are presently limited, but suggest low risk of malformation with elevated risk of low birth weight.

OBJECTIVE

To calculate the major congenital malformation (MCM) rate of zonisamide in human pregnancy and assess for a signal of any specific malformation pattern and associations with birth weight.

METHODS AND MATERIALS

Data were obtained from the UK and Ireland Epilepsy and Pregnancy register (UKIEPR) which is an observational, registration, and follow up study from December 1996 to July 2020. Eligibility criteria were use of zonisamide and to have been referred to the UKIEPR before the outcome of the pregnancy was known. Primary outcome was evidence of MCM.

RESULTS

From December 1996 through July 2020 there were 112 cases of first trimester exposure to zonisamide, including 26 monotherapy cases. There were 3 MCM for monotherapy cases (MCM rate 13.0% (95% confidence interval 4.5-32.1)), and 5 MCM for polytherapy cases (MCM rate 6.9% (95% confidence interval 3.0-15.2)). While the median birth weight was on 71st and 44th centile for monotherapy and polytherapy cases respectively, there was a high rate of infants born small for gestational age (21% for both).

CONCLUSION

These data raise concerns about a signal for potential teratogenicity with zonisamide in human pregnancy. Given the low numbers reported, further data will be required to adequately counsel women who use zonisamide in pregnancy.

Principles of Epilepsy Management for Women in Their Reproductive Years

In the United States, there are over one million women with epilepsy (WWE) in their childbearing years. Pregnancy can be challenging for this population. A number of international registries have documented that children born to these women are at increased risk for major congenital malformations (MCM), lower intelligence quotient scores and neurodevelopmental disorders, when the mother is managed on antiseizure medications (ASMs). To prevent poor neonatal outcomes for this population, safe and thoughtful management strategies are necessary. We propose to divide these management strategies into five principles. These include (I) choosing suitable ASMs for the patient's seizure type, (II) choosing an ASM with the least teratogenic and cognitive side effects, (III) dosing at the lowest possible effective dosage, (IV) selecting the best ASM regimen as promptly as possible, even before a woman has her first menses, and (V) supplementing these patients with folic acid in order to try to enhance cognition and reduce neural tube defects.

Comparative effectiveness of antiepileptic drugs in juvenile myoclonic epilepsy

OBJECTIVE

To study the effectiveness and tolerability of antiepileptic drugs (AEDs) commonly used in juvenile myoclonic epilepsy (JME).

METHODS

People with JME were identified from a large database of individuals with epilepsy, which includes detailed retrospective information on AED use. We assessed secular changes in AED use and calculated rates of response (12-month seizure freedom) and adverse drug reactions (ADRs) for the five most common AEDs. Retention was modeled with a Cox proportional hazards model. We compared valproate use between males and females.

RESULTS

We included 305 people with 688 AED trials of valproate, lamotrigine, levetiracetam, carbamazepine, and topiramate. Valproate and carbamazepine were most often prescribed as the first AED. The response rate to valproate was highest among the five AEDs (42.7%), and significantly higher than response rates for lamotrigine, carbamazepine, and topiramate; the difference to the response rate to levetiracetam (37.1%) was not significant. The rates of ADRs were highest for topiramate (45.5%) and valproate (37.5%). Commonest ADRs included weight change, lethargy, and tremor. In the Cox proportional hazards model, later start year (1.10 [1.08-1.13], P < 0.001) and female sex (1.41 [1.07-1.85], P = 0.02) were associated with shorter trial duration. Valproate was associated with the longest treatment duration; trials with carbamazepine and topiramate were significantly shorter (HR [CI]: 3.29 [2.15-5.02], P < 0.001 and 1.93 [1.31-2.86], P < 0.001). The relative frequency of valproate trials shows a decreasing trend since 2003 while there is an increasing trend for levetiracetam. Fewer females than males received valproate (76.2% vs 92.6%, P = 0.001).

SIGNIFICANCE

In people with JME, valproate is an effective AED; levetiracetam emerged as an alternative. Valproate is now contraindicated in women of childbearing potential without special precautions. With appropriate selection and safeguards in place, valproate should remain available as a therapy, including as an alternative for women of childbearing potential whose seizures are resistant to other treatments.

Changing antiepilepsy drug-prescribing trends in women with epilepsy in the UK and Ireland and the impact on major congenital malformations

OBJECTIVES

After 20 years of data collection, pregnancy registers have informed prescribing practice. Various populations show trends for a reduction in valproate prescribing, which is associated with an increased risk of anatomical teratogenesis and neurodevelopmental effects in those exposed in utero. Our aim was to determine if any shifts in prescribing trends have occurred in the UK and Ireland Epilepsy and Pregnancy Register cohort and to assess if there had been any change in the overall major congenital malformation (MCM) rate over time.

METHODS

The UK and Ireland Epilepsy and Pregnancy Register, a prospective, observational, registration and follow-up study established in 1996, was used to determine the changes in antiepileptic drugs (AEDs) utilised during pregnancy and the MCM rate between 1996 and 2016. Linear regression analysis was used to assess changes in AED utilisation, and Poisson regression was used for the analysis of trends in the MCM rates.

RESULTS

Outcome data for 9247 pregnancies showed a stable percentage of monotherapy to polytherapy prescribing habits over time. After Bonferroni correction, statistically significant (p<0.003) changes were found in monotherapy prescribing with increases in lamotrigine and levetiracetam and decreases in valproate and carbamazepine use. Between 1996 and 2016, the total MCM rate showed a 2.1% reduction per year (incidence risk ratio 0.979 (95% CIs 0.956 to 1.002) but Poisson regression analysis showed that this was not statistically significant p=0.08).

CONCLUSION

Significant changes are seen in the prescribing habits in this cohort over 20 years, but a statistically significant change in the MCM rate was not detected. This work should be replicated on a larger scale to determine if significant changes are occurring in the MCM rate, which would allow a robust economic estimate of the benefits of improvements in prescribing practice and the personal effect of such changes.