Neurologic care of pregnant women with epilepsy

Seizure medication and planned pregnancy: balancing the risks and outcomes

INTRODUCTION

The therapeutic management of women with epilepsy (WWE) of childbearing age can be complicated by the need to balance maternal/fetal risks related to seizure occurrence during gestation with the potential teratogenic risks related to the use of anti-seizure medications (ASMs).

AREAS COVERED

The authors review clinical evidence on seizure-related and ASM-related risks during pregnancy. Current regulatory indications are discussed, evaluating their impact on clinical practice, and ethical implications of pharmacological decisions are debated.

EXPERT OPINION

If properly informed about the maternal/fetal risks carried by different pharmacological choices, WWE can become the final decision makers regarding their care in every phase of their life. Over the coming years, analysis of aggregated pregnancy registry data on the structural impact, on the fetus, of low doses of valproate and of newer ASMs, together with analysis of the main population study data on functional (cognitive and behavioral) outcomes, could lead to huge advances, making choosing an ASM a less complex process for the clinician and a less painful decision for the woman. Future objectives should include identification of the potential role of the pharmacogenomic profile of WWE in determining the risk of fetal malformations.

Neuropathological sequelae of developmental exposure to antiepileptic and anesthetic drugs

Glutamate (Glu) and γ-aminobutyric acid (GABA) are major neurotransmitters in the mammalian brain which regulate brain development at molecular, cellular, and systems level. Sedative, anesthetic, and antiepileptic drugs (AEDs) interact with glutamate and GABA receptors to produce their desired effects. The question is posed whether such interference with glutamatergic and GABAergic neurotransmission may exert undesired, and perhaps even detrimental effects on human brain development. Preclinical research in rodents and non-human primates has provided extensive evidence that sedative, anesthetic, and AEDs can trigger suicide of neurons and oligodendroglia, suppress neurogenesis, and inhibit normal synapse development and sculpting. Behavioral correlates in rodents and non-human primates consist of long-lasting cognitive impairment. Retrospective clinical studies in humans exposed to anesthetics or AEDs in utero, during infancy or early childhood have delivered conflicting but concerning results in terms of a correlation between drug exposure and impaired neurodevelopmental outcomes. Prospective studies are currently ongoing. This review provides a short overview of the current state of knowledge on this topic.

Obstetric outcome in women with epilepsy: a hospital-based, retrospective study

OBJECTIVE

To report the complications during pregnancy and delivery in women with epilepsy, compared with a control group without epilepsy, with special focus on potential risk factors, such as epilepsy severity and dosage of antiepileptic drugs.

DESIGN

Hospital-based retrospective study.

SETTING

Data from pregnancy notification forms and hospital case records.

POPULATION

Women with a past or present history of epilepsy (n = 205) delivered in Bergen, Norway, in the period 1999-2006, and a matched control group of women (n = 205) without epilepsy.

METHODS

Data were compared and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by multiple logistic regression models.

MAIN OUTCOME MEASURES

Pre-eclampsia (mild and severe), gestational hypertension, vaginal bleeding (early and late), caesarean section, vaginal operative delivery, postpartum haemorrhage and major malformations.

RESULTS

Women with epilepsy using antiepileptic drugs had an increased risk of severe pre-eclampsia (OR, 5.0; 95% CI, 1.3-19.9), bleeding in early pregnancy (OR, 6.4; 95% CI, 2.7-15.2), induction (OR, 2.3; 95% CI, 1.2-4.3) and caesarean section (OR, 2.5; 95% CI, 1.4-4.7) adjusted for maternal age, parity, education, smoking, medical conditions and body mass index ≥30 kg/m(2) . There was also an increased risk of malformations in the offspring (OR, 7.1; 95% CI, 1.4-36.6). Women without antiepileptic drug use had increased risks of forceps delivery and preterm birth. Active epilepsy (seizures during the last 5 years) versus nonactive epilepsy did not discriminate for any of these complications; 84.5% of women with epilepsy and antiepileptic drug use were using folate.

CONCLUSION

Women with epilepsy using antiepileptic drugs had an increased risk of pregnancy and delivery complications, whereas women not using antiepileptic drugs had few complications. Seizures, high doses of antiepileptic drugs, obesity and lack of folate could not explain these increased risks.

Difficulties in Treatment and Management of Epilepsy and Challenges in New Drug Development

Epilepsy is a serious neurological disorder that affects around 50 million people worldwide. Almost 30% of epileptic patients suffer from pharmacoresistance, which is associated with social isolation, dependent behaviour, low marriage rates, unemployment, psychological issues and reduced quality of life. Currently available antiepileptic drugs have a limited efficacy, and their negative properties limit their use and cause difficulties in patient management. Antiepileptic drugs can provide only symptomatic relief as these drugs suppress seizures but do not have ability to cure epileptogenesis. The long term use of antiepileptic drugs is limited due to their adverse effects, withdrawal symptoms, deleterious interactions with other drugs and economic burden, especially in developing countries. Furthermore, some of the available antiepileptic drugs may even potentiate certain type of seizures. Several in vivo and in vitro animal models have been proposed and many new antiepileptic drugs have been marketed recently, but large numbers of patients are still pharmacoresistant. This review will highlight the difficulties in treatment and management of epilepsy and the limitations of available antiepileptic drugs and animal seizure models.

Prenatal effects of antiepileptic drugs

Antiepileptic drugs (AEDs) target ion channels and neurotransmitter systems in the brain; these same targets are responsible for regulation of processes essential for brain development. In this review, experimental findings on adverse effects of AEDs in the developing mammalian brain will be presented, including interference with physiological apoptotic cell death, cell proliferation and migration, neurogenesis, axonal arborization, synaptogenesis, and synaptic plasticity.

Pregnancy, epilepsy, and anticonvulsants

The majority of epileptic disorders are not self-limiting over time, and therefore require a long-lasting and often even lifelong antiepileptic drug (AED) treatment, in Wi/omen with epilepsy, the influence of their disease on the possibility and course of pregnancies, as well as the potential impact of the AED treatment on mother and child, are crucial questions.

This review addresses the clinically relevant knovledge concerning the impact of the disease itself and the AED treatment on fertility, pregnancy, delivery, the postpartum period, and teratogenicity. Some of the new AEDs appear to have a favorable profile due to a lack of clinically relevant interactions and promising teratogenic profiles. However, the finding of decreases in lamotrigine serum concentrations during hormonal contraception and pregnancy is an instructive example, shovt/ing that ongoing studies are urgently needed to further investigate stillunanswered questions. Several prospective multinational surveys are currently being performed, and should add essential information in this context.

Prophylactic treatment of bipolar disorder in pregnancy and breastfeeding: focus on emerging mood stabilizers

OBJECTIVES

Bipolar disorders are reported to have a high incidence during childbearing years and the need may arise to start or continue a pharmacological treatment during pregnancy and the postpartum period. In the last few years several investigations have evaluated the efficacy of emerging mood-stabilizing agents in the treatment of bipolar disorders, such as lamotrigine, olanzapine, risperidone, quetiapine, aripiprazole and ziprasidone. A number of studies, which examined the use of oxcarbazepine, point to its potential usefulness in prophylactic treatment. The aim of this review is to compare information from the literature on the safety of lamotrigine, oxcarbazepine, risperidone, olanzapine, and quetiapine to the safety data on classic mood stabilizers during pregnancy and the postpartum period.

METHODS

A computerized search carried out from 1980 to April 5, 2006 led to the summarization of the results. (References were updated after acceptance and prior to publication.)

RESULTS

Emerging mood stabilizers show uncertain safety parameters in pregnancy and lactation. Limited information on lamotrigine and oxcarbazepine does not suggest a clear increase in teratogenicity, while olanzapine appears to be associated with a higher risk of metabolic complications in pregnant women. Data about risperidone and quetiapine are still inconclusive. Finally, the literature on the safety of these compounds in breastfeeding is anecdotal.

CONCLUSIONS

Untreated pregnant bipolar women are at an increased risk of poor obstetrical outcomes and relapse of affective symptoms. On the other hand, classic antiepileptic drugs are well-known human teratogens, whereas data on lithium are partially ambiguous. The safety of emerging mood stabilizers in pregnancy and breastfeeding has not been examined extensively. Therefore, when approaching bipolar disorder, if possible, each episode must be considered separately.

The frequency of neonatal morbidity after exposure to antiepileptic drugs in utero

OBJECTIVES

To investigate the frequency of malformations, fetal growth retardation, cerebral hemorrhage and neonatal withdrawal symptoms in newborns exposed to antiepileptic drugs (AEDs) in utero.

DESIGN

Population of the northeastern part of Slovenia (pregnant women and newborns between 1998 and 2002).

METHODS

Data on newborns born between 1998 and 2002 of 37 epileptic mothers taking AEDs in pregnancy, of 32 epileptic mothers not taking AEDs in pregnancy and of 211 mothers healthy in pregnancy were ascertained from hospital obstetric and neonatal records and included in the study. The health status of 270 newborns was assessed.

MAIN OUTCOME MEASURES

frequency of congenital malformations, growth retardation (SFD), intracranial hemorrhage, feeding problems and withdrawal symptoms.

RESULTS

In the group not exposed to antiepileptic drugs (32 neonates), two (2.9%) had germinal matrix hemorrhage grade I, one (1.4%) was small for date (SFD) and one (1.4%) had feeding problems. In the group exposed to antiepileptic drugs (37 neonates), nine (13%) had germinal matrix hemorrhage grade I, six (8.6%) were SFD, five (7.24%) had feeding problems, four (5.8%) had withdrawal symptoms and three (4.3%) "macro" congenital anomalies. Among neonatal problems in the control non-exposed group of newborns of 211 healthy women we identified 23 (10.9%) newborns who were SFD, 5 (2.4%) cases with germinal matrix hemorrhage grade I, 5 (2.4%) cases with major congenital malformations and 7 (3.3%) cases with feeding problems.

CONCLUSIONS

Prenatal antiepileptic drug exposure in the setting of maternal epilepsy is associated with increased risk of neonatal morbidity. In our study a particularly significant connection was established between carbamazepine therapy during pregnancy and cerebral hemorrhage in the neonates.

Treatment considerations during pregnancy for women with epilepsy

Women with epilepsy have many special considerations; one of the most important of these is the risk and management of pregnancy. Both recurrent seizures during pregnancy and antiepileptic medications may have adverse maternal-fetal outcomes. Multiple registries of pregnancy outcomes for women with epilepsy worldwide are underway and data from these studies are emerging. Converging evidence from the registries thus far indicates an increased risk of major fetal congenital malformations with valproate exposure and one registry has shown an increased risk with phenobarbital exposure; further supporting evidence of the phenobarbital risk is needed.

Antiepileptic drugs and apoptosis in the developing brain

Epilepsy is the most common neurologic disorder in young humans. Antiepileptic drugs (AEDs), used to treat seizures in children, infants, and pregnant women, cause cognitive impairment, microcephaly, and birth defects by unknown mechanisms. We tested whether common AEDs cause neurodegeneration in the developing rat brain. Rats aged 3-30 days received phenytoin, phenobarbital, diazepam, clonazepam, vigabatrin, or valproic acid. Histologic examination of the brains revealed that these drugs cause widespread and dose-dependent apoptotic neurodegeneration in the developing rat brain during the brain growth spurt period. Apoptotic neurodegeneration was triggered at plasma drug levels relevant for seizure control in humans. Antiepileptic drugs lead to reduced expression of neurotrophins and decreased concentrations of the active forms of ERK1/2, RAF, and AKT. beta-Estradiol, which stimulates pathways that are activated by neurotrophins, ameliorated AEDs-induced apoptotic neurodegeneration. Our findings present one possible mechanism to explain cognitive impairment and reduced brain mass associated with pre- or postnatal exposure of humans to antiepileptic therapy.

Antiepileptic drugs and apoptotic neurodegeneration in the developing brain

Epilepsy is the most common neurological disorder of young humans. Each year 150,000 children in the United States experience their first seizure. Antiepileptic drugs (AEDs), used to treat seizures in children, infants, and pregnant women, cause cognitive impairment, microcephaly, and birth defects. The cause of unwanted effects of therapy with AEDs is unknown. Here we reveal that phenytoin, phenobarbital, diazepam, clonazepam, vigabatrin, and valproate cause apoptotic neurodegeneration in the developing rat brain at plasma concentrations relevant for seizure control in humans. Neuronal death is associated with reduced expression of neurotrophins and decreased concentrations of survival-promoting proteins in the brain. beta-Estradiol, which stimulates pathways that are activated by neurotrophins, ameliorates AED-induced apoptotic neurodegeneration. Our findings present one possible mechanism to explain cognitive impairment and reduced brain mass associated with prenatal or postnatal exposure of humans to antiepileptic therapy.

Additional educational needs in children born to mothers with epilepsy

OBJECTIVES

To examine the relative risks of additional educational needs (AENs) in children exposed to antiepileptic drug (AED) monotherapy and polytherapy regimes in utero.

METHODS

A retrospective survey of women between the ages of 16 to 40 registered at the Mersey Regional Epilepsy Clinic, who received a postal questionnaire concerning their experience of pregnancy and the subsequent schooling of live-born children.

RESULTS

721 (57%) women of the 1267 approached returned an adequately completed questionnaire; 330 (46%) had given birth to at least one live-born child. Information was collected on 594 children, 400 of whom were of school age (4-18). 150 (37.5%) had been exposed to monotherapy in utero, 74 (18.5%) were exposed to polytherapy, and 176 were not exposed to any AEDs. The odds ratio of AENs for all children exposed to AEDs in utero compared with those unexposed was 1.49 (95% confidence interval (95% CI) 0.83 -2.67). Odds ratios for AENs for each therapy subgroup compared with those unexposed were also calculated for all children. Those exposed to valproate monotherapy had an odds ratio of 3.4 (95% CI 1.63-7.10) by contrast with an odds ratio of 0.26 (95% CI 0.06- 1.15) for carbamazepine. Polytherapy including valproate had similarly high odds ratios for AENs compared with those unexposed of 2.51 ( 95% CI 1.04-6.07) versus the odds ratio of 1.51 ( 95% CI 0.56-4.07) for polytherapy excluding valproate.

CONCLUSIONS

Although the findings should be treated with caution, they suggest that monotherapy or polytherapy with valproate during pregnancy carries particular risks for the development of children exposed in utero.