Psychomotor development in preschool children exposed to antiepileptic drugs in utero

Neurodevelopmental and Functional Outcomes Following In Utero Exposure to Antiseizure Medication: A Systematic Review

BACKGROUND AND OBJECTIVES

To undertake a systematic review of the available literature to examine the relationship between prenatal antiseizure medication (ASM) exposure and adverse postnatal neurodevelopmental outcomes, focusing on social, emotional, behavioral, and adaptive domains of human function, and the frequency of neurodevelopmental and psychiatric disorders in ASM-exposed offspring.

METHODS

Electronic searches of MEDLINE, PsychINFO, and EMBASE were conducted and limited to studies published between 1990 and 2023 in English. Studies were eligible if they prospectively or retrospectively reported neurodevelopmental outcomes of ASM-exposed offspring. The Newcastle-Ottawa scale was used to conduct methodologic quality assessments of included studies, and a narrative synthesis integrated the review findings.

RESULTS

Forty-three studies were included. Valproate has been consistently associated with a 2- to 4-fold increased risk of autism spectrum disorder (ASD), 2- to 5-fold increased risk of intellectual disability (ID), and poor adaptive functioning. Growing evidence indicates that topiramate is associated with a 2-fold increased risk of ASD and 3- to 4-fold increased risk of ID. The risks of adverse neurodevelopmental outcomes for valproate and topiramate seem to be dose dependent. Phenobarbital has been suggested to be associated with deleterious neurodevelopmental effects, but data are limited. Levetiracetam has recently been linked with an increased risk of attention deficit hyperactivity disorder and anxiety disorders in a single study. Carbamazepine has been associated with variable neurodevelopmental outcomes. Lamotrigine seems to be "safe" in terms of postnatal neurodevelopment. Data for oxcarbazepine, phenytoin, and clonazepam are limited but seem to have little-to-no risk of adverse outcomes. Evidence for the remaining ASMs, including gabapentin, pregabalin, lacosamide, zonisamide, clobazam, perampanel, ethosuximide, or brivaracetam, is lacking. Several methodologic limitations impeded data synthesis, including heterogeneity in outcome measures and small samples of monotherapy exposures.

DISCUSSION

The findings of this review support the conclusion that valproate and topiramate use during pregnancy is associated with a significantly increased risk of neurodevelopmental effects on the fetus. Apart from lamotrigine, which seems to be free of adverse neurodevelopmental effects, data for the other ASMs are mixed or inadequate to draw definite conclusions. Further research into the neurodevelopmental effects of prenatal exposure to ASMs, including most newer agents, is much needed.

An Update on Maternal Use of Antiepileptic Medications in Pregnancy and Neurodevelopment Outcomes

Antiepileptic drugs (AEDs) are prescribed commonly to women of childbearing age. In utero exposure to some AEDs can have significant cognitive and behavioral consequences for the unborn child. Recently, prospective studies of women taking AEDs during pregnancy have added significantly to our understanding of cognitive and behavioral teratogenic risks posed by fetal AED exposure. Valproate is clearly associated with impaired cognitive development as well as an increased risk of disorders such as autism and autism spectrum disorder. Exposure to carbamazepine, lamotrigine, levetiracetam, or phenytoin monotherapy is associated with more favorable cognitive and behavioral outcomes than valproate, but more data are required to clarify if these AEDs have more subtle effects on cognition and behavior. There are insufficient data on the developmental effects of other AEDs in humans. Further, the underlying mechanisms of cognitive teratogenesis are poorly understood, including the genetic factors that affect susceptibility to AEDs.

Neurodevelopmental effects of fetal antiepileptic drug exposure

Many studies investigating cognitive outcomes in children of women with epilepsy report an increased risk of mental impairment. Verbal scores on neuropsychometric measures may be selectively more involved. While a variety of factors contribute to the cognitive problems of children of women with epilepsy, antiepileptic drugs (AEDs) appear to play a major role. The mechanisms by which AEDs affect neurodevelopmental outcomes remain poorly defined. Animal models suggest that AED-induced apoptosis, altered neurotransmitter environment, and impaired synaptogenesis are some of the mechanisms responsible for cognitive and behavioral teratogenesis. AEDs that are known to induce apoptosis, such as valproate, appear to affect children's neurodevelopment in a more severe fashion. Fetal valproate exposure has dose-dependent associations with reduced cognitive abilities across a range of domains, and these appear to persist at least until the age of 6. Some studies have shown neurodevelopmental deficiencies associated with the use of phenobarbital and possibly phenytoin. So far, most of the investigations available suggest that fetal exposures to lamotrigine or levetiracetam are safer with regard to cognition when compared with other AEDs. Studies on carbamazepine show contradictory results, but most information available suggests that major poor cognitive outcomes should not be attributed to this medication. Overall, children exposed to polytherapy prenatally appear to have worse cognitive and behavioral outcomes compared with children exposed to monotherapy, and with the unexposed. There is an increase risk of neurodevelopmental deficits when polytherapy involves the use of valproate versus other agents.

Cognitive outcomes of prenatal antiepileptic drug exposure

Antiepileptic drugs (AEDs) have been known to have teratogenic effects for a little over 50 years. While early reports focused on fetal malformations, there has been an increasing amount of data over the last few decades exploring the cognitive outcomes of offspring exposed to AEDs in utero. Although the challenges of confounding factors and varied methodologies have led to inconsistent results, the negative impact of some of the agents, such as valproate, have become clear. Further studies are needed to evaluate the cognitive effects of prenatal exposure to many AEDs which have not been tested, to clarify the effects of existing AEDs which have yielded mixed results, and to better understand the effects of polytherapy. Research in animal models is warranted to screen AEDs for their effects on cognition in exposed offspring and to further our understanding of the underlying mechanisms by which AEDs exert their harmful effects on the developing brain. And finally, new AEDs without these harmful effects and agents which can prevent or reverse the negative consequences imparted by AED therapy on cognition should be sought.

IQ at 6 years after in utero exposure to antiepileptic drugs: a controlled cohort study

OBJECTIVE

To delineate the risk to child IQ associated with frequently prescribed antiepileptic drugs.

METHODS

Children born to women with epilepsy (n = 243) and women without epilepsy (n = 287) were recruited during pregnancy and followed prospectively. Of these, 408 were blindly assessed at 6 years of age. Maternal and child demographics were collected and entered into statistical models.

RESULTS

The adjusted mean IQ was 9.7 points lower (95% confidence interval [CI] -4.9 to -14.6; p < 0.001) for children exposed to high-dose (>800 mg daily) valproate, with a similar significant effect observed for the verbal, nonverbal, and spatial subscales. Children exposed to high-dose valproate had an 8-fold increased need of educational intervention relative to control children (adjusted relative risk, 95% CI 8.0, 2.5-19.7; p < 0.001). Valproate at doses <800 mg daily was not associated with reduced IQ, but was associated with impaired verbal abilities (-5.6, 95% CI -11.1 to -0.1; p = 0.04) and a 6-fold increase in educational intervention (95% CI 1.4-18.0; p = 0.01). In utero exposure to carbamazepine or lamotrigine did not have a significant effect on IQ, but carbamazepine was associated with reduced verbal abilities (-4.2, 95% CI -0.6 to -7.8; p = 0.02) and increased frequency of IQ <85.

CONCLUSIONS

Consistent with data from younger cohorts, school-aged children exposed to valproate at maternal doses more than 800 mg daily continue to experience significantly poorer cognitive development than control children or children exposed to lamotrigine and carbamazepine.

Treatment for epilepsy in pregnancy: neurodevelopmental outcomes in the child

BACKGROUND

Accumulating evidence suggests an association between prenatal exposure to antiepileptic drugs (AEDs) and increased risk of both physical anomalies and neurodevelopmental impairment. Neurodevelopmental impairment is characterised by either a specific deficit or a constellation of deficits across cognitive, motor and social skills and can be transient or continuous into adulthood. It is of paramount importance that these potential risks are identified, minimised and communicated clearly to women with epilepsy.

OBJECTIVES

To assess the effects of prenatal exposure to commonly prescribed AEDs on neurodevelopmental outcomes in the child and to assess the methodological quality of the evidence.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialized Register (May 2014), Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2014, Issue 4), MEDLINE (via Ovid) (1946 to May 2014), EMBASE (May 2014), Pharmline (May 2014) and Reprotox (May 2014). No language restrictions were imposed. Conference abstracts from the last five years were reviewed along with reference lists from the included studies.

SELECTION CRITERIA

Prospective cohort controlled studies, cohort studies set within pregnancy registers and randomised controlled trials were selected for inclusion. Participants were women with epilepsy taking AED treatment; the two control groups were women without epilepsy and women with epilepsy who were not taking AEDs during pregnancy.

DATA COLLECTION AND ANALYSIS

Three authors (RB, JW and JG) independently selected studies for inclusion. Data extraction and risk of bias assessments were completed by five authors (RB, JW, AS, NA, AJM). The primary outcome was global cognitive functioning. Secondary outcomes included deficits in specific cognitive domains or prevalence of neurodevelopmental disorders. Due to substantial variation in study design and outcome reporting only limited data synthesis was possible.

MAIN RESULTS

Twenty-two prospective cohort studies were included and six registry based studies. Study quality varied. More recent studies tended to be larger and to report individual AED outcomes from blinded assessments, which indicate improved methodological quality.The developmental quotient (DQ) was lower in children exposed to carbamazepine (CBZ) (n = 50) than in children born to women without epilepsy (n = 79); mean difference (MD) of -5.58 (95% confidence interval (CI) -10.83 to -0.34, P = 0.04). The DQ of children exposed to CBZ (n = 163) was also lower compared to children of women with untreated epilepsy (n = 58) (MD -7.22, 95% CI -12.76 to - 1.67, P = 0.01). Further analysis using a random-effects model indicated that these results were due to variability within the studies and that there was no significant association with CBZ. The intelligence quotient (IQ) of older children exposed to CBZ (n = 150) was not lower than that of children born to women without epilepsy (n = 552) (MD -0.03, 95% CI -3.08 to 3.01, P = 0.98). Similarly, children exposed to CBZ (n = 163) were not poorer in terms of IQ in comparison to the children of women with untreated epilepsy (n = 87) (MD 1.84, 95% CI -2.13 to 5.80, P = 0.36). The DQ in children exposed to sodium valproate (VPA) (n = 123) was lower than the DQ in children of women with untreated epilepsy (n = 58) (MD -8.72, 95% -14.31 to -3.14, P = 0.002). The IQ of children exposed to VPA (n = 76) was lower than for children born to women without epilepsy (n = 552) (MD -8.94, 95% CI -11.96 to -5.92, P < 0.00001). Children exposed to VPA (n = 89) also had lower IQ than children born to women with untreated epilepsy (n = 87) (MD -8.17, 95% CI -12.80 to -3.55, P = 0.0005).In terms of drug comparisons, in younger children there was no significant difference in the DQ of children exposed to CBZ (n = 210) versus VPA (n=160) (MD 4.16, 95% CI -0.21 to 8.54, P = 0.06). However, the IQ of children exposed to VPA (n = 112) was significantly lower than for those exposed to CBZ (n = 191) (MD 8.69, 95% CI 5.51 to 11.87, P < 0.00001). The IQ of children exposed to CBZ (n = 78) versus lamotrigine (LTG) (n = 84) was not significantly different (MD -1.62, 95% CI -5.44 to 2.21, P = 0.41). There was no significant difference in the DQ of children exposed to CBZ (n = 172) versus phenytoin (PHT) (n = 87) (MD 3.02, 95% CI -2.41 to 8.46, P = 0.28). The IQ abilities of children exposed to CBZ (n = 75) were not different from the abilities of children exposed to PHT (n = 45) (MD -3.30, 95% CI -7.91 to 1.30, P = 0.16). IQ was significantly lower for children exposed to VPA (n = 74) versus LTG (n = 84) (MD -10.80, 95% CI -14.42 to -7.17, P < 0.00001). DQ was higher in children exposed to PHT (n = 80) versus VPA (n = 108) (MD 7.04, 95% CI 0.44 to 13.65, P = 0.04). Similarly IQ was higher in children exposed to PHT (n = 45) versus VPA (n = 61) (MD 9.25, 95% CI 4.78 to 13.72, P < 0.0001). A dose effect for VPA was reported in six studies, with higher doses (800 to 1000 mg daily or above) associated with a poorer cognitive outcome in the child. We identified no convincing evidence of a dose effect for CBZ, PHT or LTG. Studies not included in the meta-analysis were reported narratively, the majority of which supported the findings of the meta-analyses.

AUTHORS' CONCLUSIONS

The most important finding is the reduction in IQ in the VPA exposed group, which are sufficient to affect education and occupational outcomes in later life. However, for some women VPA is the most effective drug at controlling seizures. Informed treatment decisions require detailed counselling about these risks at treatment initiation and at pre-conceptual counselling. We have insufficient data about newer AEDs, some of which are commonly prescribed, and further research is required. Most women with epilepsy should continue their medication during pregnancy as uncontrolled seizures also carries a maternal risk.

Long-term consequences after exposure to antiepileptic drugs in utero

Most pregnant women with epilepsy need pharmacological treatment during pregnancy. Children exposed to antiepileptic drugs have an increased risk of being born with major malformations. Some antiepileptic drugs seem to have negative effects on psychomotor or cognitive development in children exposed during foetal life. Neither carbamazepine nor lamotrigine in monotherapy seem to affect the cognition of exposed children. Several studies have shown negative effects on the long-term neurodevelopment of children prenatally exposed to valproic acid or polytherapy (two or more antiepileptic drugs during pregnancy). For most of the newer antiepileptic drugs there are insufficient data regarding long-term outcome.

Fetal growth restriction and birth defects with newer and older antiepileptic drugs during pregnancy

The primary aim of this study was to assess the risks of fetal growth restriction and birth defects in children exposed prenatally to newer and older antiepileptic drugs, using an unselected epilepsy cohort. Deliveries recorded in the compulsory Medical Birth Registry of Norway 1999-2011 formed the study population. All 2,600 children exposed to antiepileptic drugs during pregnancy were compared to all 771,412 unexposed children born to women without epilepsy. Children of untreated mothers with epilepsy served as an internal control group. The main outcomes were small for gestational age birth weight and head circumference, and major congenital malformations. Children exposed to antiepileptic drugs had a moderate risk of growth restriction. Infants exposed to topiramate had a considerable risk of microcephaly (11.4 vs. 2.4 %; OR 4.8; CI 2.5-9.3) and small for gestational age birth weight (24.4 vs. 8.9 %; OR 3.1; 95 % CI 1.9-5.3). Carbamazepine, lamotrigine, levetiracetam, oxcarbazepine, gabapentin, and pregabalin had low malformation rates, whereas topiramate tended to have an elevated malformation rate. Valproate monotherapy was associated with a significant risk of birth defects (6.3 vs. 2.9 %; OR 2.5; CI 1.6-3.8), and specifically with septal heart defects and hypospadias. For mothers using valproate, the presence of major birth defect in one child was associated with a markedly increased risk for the siblings (42.9 vs. 6.7 %; OR 10.4; CI 2.3-46.7). Children of untreated mothers with epilepsy had malformation risk similar to the reference group. In conclusion, topiramate was associated with a substantial risk of fetal growth restriction, and possibly an increased malformation rate. Other newer-generation antiepileptic drugs had a low malformation rate. Valproate monotherapy had a significant malformation risk, especially in repeated pregnancies.

Exposure to antiepileptic drugs in utero and child development: a prospective population-based study

PURPOSE

Antiepileptic drugs may cause congenital malformations. Less is known about the effect on development in infancy and childhood. The aim of this study was to examine whether exposure to antiepileptic drugs during pregnancy has an effect on early child development.

METHODS

From mid-1999 through December 2008, children of mothers recruited at 13-17 weeks of pregnancy were studied in the ongoing prospective Norwegian Mother and Child Cohort Study. Information on birth outcomes were obtained from the Medical Birth Registry (108,264 children), and mothers reported on their child's motor development, language, social skills, and autistic traits using items from standardized screening tools at 18 months (61,351 children) and 36 months (44,147 children) of age. The relative risk of adverse outcomes in children according to maternal or paternal epilepsy with and without prenatal exposure to antiepileptic drugs was estimated as odds ratios (ORs), using logistic regression with adjustment for maternal age, parity, education, smoking, depression/anxiety, folate supplementation, and child congenital malformation or low birth weight.

KEY FINDINGS

A total of 333 children were exposed to antiepileptic drugs in utero. At 18 months, the exposed children had increased risk of abnormal scores for gross motor skills (7.1% vs. 2.9%; OR 2.0, 95% confidence interval [CI] 1.1-3.7) and autistic traits (3.5% vs. 0.9%; OR 2.7, CI 1.1-6.7) compared to children of parents without epilepsy. At 36 months, the exposed children had increased risk of abnormal score for gross motor skills (7.5% vs. 3.3%; OR 2.2, CI 1.1-4.2), sentence skills (11.2% vs. 4.8%; OR 2.1, CI 1.2-3.6), and autistic traits (6.0% vs. 1.5%; OR 3.4, CI 1.6-7.0). The drug-exposed children also had increased risk of congenital malformations (6.1% vs. 2.9%; OR 2.1, CI 1.4-3.4), but exclusion of congenital malformations did not affect the risk of adverse development. Children born to women with epilepsy who did not use antiepileptic drugs had no increased risks. Children of fathers with epilepsy generally scored within the normal range.

SIGNIFICANCE

Exposure to antiepileptic drugs during pregnancy is associated with adverse development at 18 and 36 months of age, measured as low scores within key developmental domains rated by mothers. Exposures to valproate, lamotrigine, carbamazepine, or multiple antiepileptic drugs were associated with adverse outcome within different developmental domains.

Impact of early life exposure to antiepileptic drugs on neurobehavioral outcomes based on laboratory animal and clinical research

Epilepsy affects approximately 1% of children under the age of 15, making it a very common neurological disorder in the pediatric population (Russ et al., 2012). In addition, ~0.4-0.8% of all pregnant women have some form of epilepsy (Hauser et al., 1996a,b; Borthen et al., 2009; Krishnamurthy, 2012). Despite the potential deleterious effects of antiepileptic drugs (AEDs) on the developing brain, their use is still required for seizure control in pregnant women (Krishnamurthy, 2012), and they represent the standard approach for treating children with epilepsy (Chu-Shore and Thiele, 2010; Quach et al., 2010; Verrotti et al., 2011). Even when AEDs are effective, there are potential side effects, including cognitive and affective changes or altered sleep and appetite. The consequences of AED exposure in development have been studied extensively (Canger et al., 1999; Modi et al., 2011a,b; Oguni, 2011). Despite intensive study, there is still debate about the long-term consequences of early life AED exposure. Here, we consider the evidence to date that AED exposure, either prenatally or in early postnatal life, has significant adverse effects on the developing brain and incorporate studies of laboratory animals as well as those of patients. We also note the areas of research where greater clarity seems critical in order to make significant advances. A greater understanding of the impact of AEDs on somatic, cognitive and behavioral development has substantial value because it has the potential to inform clinical practice and guide studies aimed at understanding the genetic and molecular bases of comorbid pathologies associated with common treatment regimens. Understanding these effects has the potential to lead to AEDs with fewer side effects. Such advances would expand treatment options, diminish the risk associated with AED exposure in susceptible populations, and improve the quality of life and health outcomes of children with epilepsy and children born to women who took AEDs during pregnancy.

Neurological and psychiatric sequelae of developmental exposure to antiepileptic drugs

The neurons in the developing mammalian brain are susceptible to antiepileptic drug (AED) effects. It is known that later in life deficits in cognitive performance as well as psychiatric deficits can manifest after early AED exposure. The extent of these deficits will be addressed. This review will attempt to draw parallels between the existent animal models and human studies. Through analysis of these studies, important future research will be elucidated and possible new and emerging therapies will be discussed.

Antiepileptic drugs in women with epilepsy during pregnancy

Prescribing antiepileptic drugs (AEDs) in pregnancy is a challenge to the clinician. A multitude of questions arise that must be addressed even prior to conception. In women with proven epilepsy, it may be dangerous to stop or even change the AED regimen during pregnancy. Changes could lead to injury or death in both the mother and the fetus. In the rare cases when discontinuing an AED is plausible, it should be done methodically in consultation with the physician prior to conception. Most women with epilepsy are consigned to continue their AEDs before, during and after pregnancy. The metabolism of AEDs may change drastically during pregnancy. These changes must be addressed by the clinician. Drug levels should be monitored consistently during pregnancy. The risks to the fetus must be delineated in terms of side effects from specific drugs as well as risks from the seizure disorder itself. Many AEDs have well known teratogenic effects, and these must be elucidated to the mother. There are risks (theoretical and evidence based) for obstetrical complications, poor neonatal outcomes, congenital malformations and even cognitive effects on the child later in life. These risks are addressed in this article with respect to individual AEDs. Recommendations include but are not limited to preconception counseling, taking folate pre and post conception, prescribing the most effective AED while minimizing risks, and avoiding polytherapy and valproate if possible.

Cognitive and neurodevelopmental effects of antiepileptic drugs

This article primarily represents the contributions of two young investigators to the understanding of the neuropsychological consequences of epilepsy and its treatment. The authors have reviewed two key areas of importance: the complex relationship between cognitive dysfunction and epilepsy and the risks of cognitive dysfunction in children as a consequence of in utero exposure to antiepileptic drug treatment. The work of two young investigators is presented and future research needs are outlined.

Antiepileptic drugs and neurodevelopment: an update

In utero exposure to some antiepileptic drugs (AEDs) is associated with an increased risk of impaired cognitive development. Specifically, valproate and polytherapy exposure are each associated with an increased risk of cognitive impairment in children compared with other antiepileptic medications. The data regarding the risk to neurocognitive development imposed by maternal use of other AEDs are conflicting or insufficient at this time to draw definitive conclusions. Behavioral dysfunction including autistic spectrum disorder is also associated with maternal use of AEDs during pregnancy. Whether treatment with AEDs during childhood permanently affects cognitive neurodevelopment is yet to be determined.

Antiepileptic drug use in women of childbearing age

Research on antiepileptic drug (AED) teratogenesis has demonstrated an increased risk for valproate. The impact of these findings on current AED prescribing patterns for women of childbearing age with epilepsy is uncertain. The Neurodevelopmental Effects of Antiepileptic Drugs (NEAD) Study is an ongoing prospective multicenter observational investigation that enrolled pregnant women with epilepsy on the most common AED monotherapies from October 1999 to February 2004 (carbamazepine, lamotrigine, valproate, and phenytoin). A 2007 survey of AED use in women of childbearing age at eight NEAD centers found a total of 932 women of childbearing age with epilepsy (6% taking no AED, 53% monotherapy, 41% polytherapy). The most common monotherapies were lamotrigine or levetiracetam. Since 2004, prescriptions of carbamazepine, phenytoin, and valproate have decreased, whereas those for levetiracetam have increased. Except for the top two AED monotherapies, there were marked differences in other monotherapies and in polytherapies between U.S. and UK centers. Future investigations are needed to examine reasons for drug choice.

Practice parameter update: management issues for women with epilepsy--focus on pregnancy (an evidence-based review): teratogenesis and perinatal outcomes: report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and American Epilepsy Society

OBJECTIVE

To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy.

METHODS

Systematic review of relevant articles published between January 1985 and June 2007.

RESULTS

It is highly probable that intrauterine first-trimester valproate (VPA) exposure has higher risk of major congenital malformations (MCMs) compared to carbamazepine and possible compared to phenytoin or lamotrigine. Compared to untreated WWE, it is probable that VPA as part of polytherapy and possible that VPA as monotherapy contribute to the development of MCMs. It is probable that antiepileptic drug (AED) polytherapy as compared to monotherapy regimens contributes to the development of MCMs and to reduced cognitive outcomes. For monotherapy, intrauterine exposure to VPA probably reduces cognitive outcomes. Further, monotherapy exposure to phenytoin or phenobarbital possibly reduces cognitive outcomes. Neonates of WWE taking AEDs probably have an increased risk of being small for gestational age and possibly have an increased risk of a 1-minute Apgar score of <7.

RECOMMENDATIONS

If possible, avoidance of valproate (VPA) and antiepileptic drug (AED) polytherapy during the first trimester of pregnancy should be considered to decrease the risk of major congenital malformations (Level B). If possible, avoidance of VPA and AED polytherapy throughout pregnancy should be considered to prevent reduced cognitive outcomes (Level B). If possible, avoidance of phenytoin and phenobarbital during pregnancy may be considered to prevent reduced cognitive outcomes (Level C). Pregnancy risk stratification should reflect that the offspring of women with epilepsy taking AEDs are probably at increased risk for being small for gestational age (Level B) and possibly at increased risk of 1-minute Apgar scores of <7 (Level C).

Antiepileptic drugs during pregnancy: what is known and which AEDs seem to be safest?

Most infants born to women with epilepsy are healthy, but there are increased risks related to in utero antiepileptic drug (AED) exposure and seizures. Emerging data from pregnancy registries and other studies allow us to better balance the anatomic teratogenic and neurodevelopmental effects of AEDs against the need to maintain maternal seizure control. Several large prospective pregnancy registries demonstrate a consistent pattern of increased risk for major congenital malformations (MCMs) with valproate (VPA) use as monotherapy, compared to nonexposed populations and to other AEDs used in monotherapy. AED polytherapy likely increases risk for MCMs, but the risk is more pronounced if VPA is included. Reduced cognitive outcomes have been reported with AED polytherapy, and with use of VPA, phenobarbital (PB), and PHT as monotherapy. Dose-dependent risk has been demonstrated with VPA for MCMs and cognitive consequences. CBZ groups show normal neurodevelopment. Increased clearance of most of the AEDs occurs during pregnancy. Use of therapeutic drug monitoring during pregnancy with LTG reduces the risk for seizure worsening. The consistent findings of increased teratogenic risk for VPA should discourage use of this medication as first-line treatment in women of childbearing age.

Cognitive/behavioral teratogenetic effects of antiepileptic drugs

The majority of children of mothers with epilepsy are normal, but they are at increased risk for developmental delay. Antiepileptic drugs (AEDs) appear to play a role. Our current knowledge is reviewed, including research design issues and recommendations for future research. In animals, exposure of the immature brain to some AEDs can produce widespread neuronal apoptosis and behavioral deficits. The risks of AEDs in humans are less clear, but recent studies raise concerns, especially for valproate. There is a critical need for well-designed systematic research to improve our understanding of AED effects on the fetal brain.

Neuropsychological outcomes in children of mothers with epilepsy

The study investigated the nature of the effects of maternal epilepsy on cognitive performance of the offspring. One hundred fifty-four children of mothers with epilepsy aged 5 to 11 years (study group), along with 130 control children, comparable with respect to IQ, socio-economic status, age, and gender underwent a neuropsychological assessment using subtests from the NEPSY: A Developmental Neuropsychological Assessment, tapping attentional, auditory-verbal, visuomotor, fine motor, and memory abilities. The study group scored significantly lower than the controls on measures of attention, memory, and fine-motor function. Deficits were more marked in but not limited to the subset of the study group exposed to maternal medication in utero. Group differences on auditory attention were found only in younger children. Valproate-exposed children obtained lower scores on sentence repetition, as well as on the more demanding part of a test of auditory attention, than other children in the study group, suggesting weaknesses in working memory in the former subgroup. Confounding by maternal epilepsy type and polytherapy complicate interpretation of this finding. Differences between subsets of children not exposed to anti-epileptic drugs in utero and controls suggest that both drug exposure and genetic factors may contribute to cognitive deficits associated with maternal epilepsy.

The longer term outcome of children born to mothers with epilepsy

OBJECTIVES

To determine the prevalence of cognitive delay and possible associated dysmorphic features in children exposed to antiepileptic drugs (AEDs) in utero.

DESIGN

Retrospective study of children born to mothers with epilepsy.

SETTING

Regional epilepsy clinics in Liverpool and Manchester, UK.

PARTICIPANTS

Children aged between 6 months and 16 years born to mothers with epilepsy.

MAIN OUTCOME MEASURES

Structured interviews, hospital records, clinical examination, and psychometric tests (Wechsler) were used to assess exposure and intelligence quotient (IQ). Blinded assessment of photographs was used to score children with characteristic dysmorphic features.

RESULTS

A total of 249 children aged 6 and over were studied: 41 were exposed to sodium valproate, 52 to carbamazepine, 21 to phenytoin, 49 to polytherapy, and 80 were unexposed. Mean verbal IQ was significantly lower in the valproate group compared to unexposed and other monotherapy groups. Multiple regression analysis showed that both valproate exposure and frequent tonic-clonic seizures in pregnancy were significantly associated with a lower verbal IQ despite adjusting for other confounding factors. There was a significant negative correlation between dysmorphic features and verbal IQ in children exposed to valproate.

CONCLUSIONS

This study identifies valproate as a drug carrying potential risks for developmental delay and cognitive impairment and is the first to suggest that frequent tonic-clonic seizures have a similar effect. Our results need to be interpreted with caution given their retrospective nature. Women with epilepsy need careful counselling about individual risk benefit of AED treatment before pregnancy.