Malformation Rates in Children of Women with Untreated Epilepsy

Efficacy of medical care of epileptic pregnant women based on the rate of congenital abnormalities in their offspring

The objective of the present study was to check the efficacy of progress in the medical care of epileptic pregnant women on the basis of the reduction of different congenital abnormalities (CAs) in their offspring. First, the prevalence of medically recorded epilepsy was compared in 95 pregnant women who later had offspring with different CAs (case group) and 90 pregnant women who later delivered newborn infants without CA (control group) and matched to cases in the Hungarian Case-Control Surveillance System of Congenital Abnormalities, 1980-1996. Second, the rate of different CAs was compared in the offspring of epileptic pregnant women between 1980 and 1989 and 1990-1996. Cleft lip with or without cleft palate, cleft palate, cardiovascular CAs, oesophageal atresia/stenosis, hypospadias and multiple CAs showed a higher risk in the offspring of pregnant women with epilepsy treated with different antiepileptic drugs, explained mainly by polytherapy. There was no higher risk for total CAs after monotherapy. There was no significantly lower rate of total CAs in the offspring of epileptic pregnant women during the second period of the study. The efficacy of special medical care of epileptic pregnant women was not shown on the basis of decrease in the rate of CAs in the offspring of epileptic pregnant women.

Antiepileptic treatment in pregnant women: morphological and behavioural effects

It is well established that children exposed to antiepileptic drugs (AEDs) in utero have an increased risk of adverse pregnancy outcomes including foetal growth retardation, major congenital malformations and impaired postnatal cognitive development. However, due to the significant maternal and foetal risks associated with uncontrolled epileptic seizures, AED treatment is generally maintained during pregnancy in the majority of women with active epilepsy. The prevalence of major malformations in children exposed to AEDs has ranged from 4 to 10%, 2-4 times higher than in the general population. More recent studies suggest a smaller increase in malformation rates. Malformation rates have consistently been higher in association with exposure to valproate than with carbamazepine and lamotrigine. Some prospective cohort studies also indicate reduced cognitive outcome in children exposed to valproate compared to carbamazepine and possibly lamotrigine. Information on pregnancy outcomes with newer generation AEDs other than lamotrigine are still insufficient.

Epilepsy, sex hormones and antiepileptic drugs in female patients

Women with epilepsy have a higher incidence of reproductive endocrine disorders than the general female population. These alterations include polycystic ovary syndrome, hyperandrogenemia, infertility, hypothalamic amenorrhea and hyperprolactinemia. Reproductive dysfunction is attributed both to epilepsy itself and to antiepileptic drugs (AEDs). Focal epileptic discharges from the temporal lobe may have a direct influence on the function of the hypothalamic-pituitary axis, thus altering the release of sex steroid hormones, including the production of luteinizing hormone, follicle-stimulating hormone, gonadotropin-releasing hormone and prolactin. AEDs may modulate hormone release from the hypothalamic-pituitary-gonadal axis and they may alter the metabolism of sex hormones and their binding proteins. Hepatic enzyme-inducing AEDs, such as carbamazepine and phenytoin, may be most clearly linked to altered metabolism of sex steroid hormones, but valproic acid, an enzyme inhibitor, has also been associated with a frequent occurrence of polycystic ovary syndrome and hyperandrogenism in women with epilepsy. Therefore, treatment of epilepsy and selection of AEDs are important for reproductive health in female patients. The aim of the present review is to critically evaluate the recently published data concerning the interactions between sex hormones, epilepsy and AEDs.

Managing antiepileptic drugs during pregnancy and lactation

PURPOSE OF REVIEW

This review discusses data on the pharmacokinetics of antiepileptic drugs (AEDs) in pregnancy and lactation, and the clinical consequences thereof, thus providing a basis for a rational management of AEDs during pregnancy and lactation.

RECENT FINDINGS

Studies have confirmed that the elimination of lamotrigine and the active metabolite of oxcarbazepine is enhanced during pregnancy. It has been established that the increased clearance of lamotrigine is caused by induction of glucuronidation. Also, the plasma concentrations of levetiracetam decline in pregnancy but the mechanism for this effect is yet to be explored. Lamotrigine is eliminated slowly in breast-fed infants, but although lamotrigine concentrations in the infant can reach pharmacological levels, no studies have reported clinically relevant adverse effects caused by lactation.

SUMMARY

Knowledge of the pharmacokinetics of AEDs in pregnancy and during lactation is important to enable optimal treatment. Gestation induced alterations in pharmacokinetics vary with the AED but also between patients and are difficult to predict. Therapeutic drug monitoring is, therefore, advisable during pregnancy and the use of the individual patient's optimal prepregnancy drug level is recommended as reference. Breastfeeding is in general safe but needs appropriate observation of the nursing infant.

Influences on seizure activity in pregnant women with epilepsy

This study evaluated whether referral to a specialized epilepsy clinic prior to pregnancy influences seizure activity during pregnancy. In addition, folic acid supplementation prior to pregnancy as a marker of intent to conceive was used to evaluate whether the use of folic acid at the time of conception correlates with the risk of seizure deterioration in pregnancy. The study population consisted of patients who had been followed in a specialized epilepsy clinic before conception (group 1, n=46) and patients who were referred to the clinic after the pregnancy was recognized (group 2, n=44). Seizure deterioration was significantly lower in group 1 than in group 2: 9% versus 32% (P<0.01). In addition, the likelihood of having taken folic acid supplements was significantly higher in group 1 (P<0.001). With some methodological limitations taken into account, it is concluded that women followed in a specialized epilepsy clinic have a lower risk of seizure deterioration during pregnancy compared with those referred after conception.

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).

Pregnancy and epilepsy: what should we tell our patients?

Women with epilepsy that plan to become pregnant can in general look forward to uneventful pregnancies and to giving birth to normal children. However, there are certain risks associated with epilepsy and antiepileptic drug (AED) treatment, and it is likely that these risks can be reduced with appropriate prepregnancy counseling. Women with epilepsy should be informed that maintained control of tonic-clonic seizures is important for their health as well as for the well-being of the fetus; that pregnancy in general has little effect on seizure control; but that pregnancy may affect plasma concentrations of AEDs, and that drug level monitoring and dosage adjustments may be needed. They should be informed of the moderately increased risk of birth defects, and that this risk appears to be higher with the use of valproate, in particular at doses above 800 mg/day. The possibility of changing from valproate to another AED should be considered, but such changes should be tried out before conception. Withdrawing or changing an AED should generally be avoided during pregnancy. Women with epilepsy on AED treatment should be encouraged to breast-feed.

Teratogenesis associated with antibipolar agents

OBJECTIVE

To review the teratogenic effects associated with the use of Food and Drug Administration-approved agents for bipolar disorder.

METHODS

A PubMed search of all English language articles published from January 1966 to December 2008 was conducted. The key search terms included all major bipolar agents, cross-referenced with: teratogenicity, teratogen, safety, pregnancy, fetus, bipolar disorder, and malformation. The search was augmented with manual reviews of relevant article reference lists as well as http://clinicaltrials.gov and http://www.fda.gov (both last accessed in April 2008). Several pregnancy registries were also reviewed to determine malformation rates as well as teratogenesis attributable to each agent. Articles selected for review were based on author consensus, adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality.

RESULTS

Valproate is associated with the highest rate of major congenital malformations (6.2%-16%). The relative risk of neural tube defects with valproate and carbamazepine is reported as approximately 1%-5% and 0.5%-1%, respectively. Preliminary evidence suggests that the relative risk for oral clefts (cleft lip or palate) is increased with lamotrigine relative to other antiepileptic drugs (AED) (ie, approximately 0.4%). The rate of major congenital malformations is higher in fetuses exposed to AED polytherapy (ie, >or=2 drugs) in comparison with AED monotherapy. Adverse neurobehavioral effects are insufficiently reported for most agents. In-utero exposure to valproate is associated with a greater risk of developmental difficulty requiring special education interventions as well as decreased verbal IQ scores. The risk of Ebstein's anomaly associated with lithium use is increased relative to the general population. The major congenital malformation rate with chlorpromazine and atypical antipsychotics is not established as being higher than a non-exposed group; the teratogenic risks associated with the olanzapine-fluoxetine combination are unknown.

CONCLUSIONS

Well-characterized risks are associated with valproate, carbamazepine, lamotrigine, and lithium. The risks associated with psychotropic drug use need to be understood in the context of significant rates of relapse and associated morbidity when discontinuing bipolar treatment during pregnancy.

Teratogenicity of antiepileptic medications

Antiepileptic drugs (AEDs) are frequently used to treat several conditions that are common in women of childbearing age, including epilepsy, headaches, and mood disorders. Moreover, as in the case of epilepsy and severe psychiatric disease, clinicians frequently do not have the option of stopping these medications or switching to another class of drugs. Overall, AEDs have been associated with an increased risk of major congenital malformations, minor anomalies, specific congenital syndromes, and developmental disorders seen in childhood. However, the differential effects of individual AEDs remain uncertain. Data are accumulating which strongly suggest that these risks are highest in patients receiving polypharmacy and valproate. There is also modest evidence to suggest an increased risk for phenobarbital. While other older AEDs appear to carry some teratogenic risk, there is not adequate evidence to further stratify their risk. Clinical and basic science research regarding newer AEDs suggests equivalent, if not safer, profiles compared with older AEDs, but these data are inconclusive. Management of women with epilepsy should include a discussion of these risks, prophylactic treatment with folic acid, and the minimal use of polypharmacy and valproate needed to maintain optimum seizure control.

Pregnancy outcome after in utero exposure to valproate : evidence of dose relationship in teratogenic effect

BACKGROUND

Valproate is a first-line antiepileptic agent and is also used in the treatment of bipolar disorder and migraine. It is a known human teratogen. The objective of the study was to evaluate the teratogenic risk of valproate.

METHODS

All callers who contacted the Israeli Teratology Information Service (TIS) between 1994 and 2004 for information about gestational exposure to valproate were enrolled in the study. After the expected date of delivery, these women were followed up by telephone interview about their pregnancy outcome using a structured questionnaire. Data obtained from women who contacted the TIS about valproate exposure during pregnancy were then compared with data obtained from callers who were counselled for nonteratogenic exposures over the same timeframe. The main outcome measure was the rate of major congenital anomalies.

RESULTS

The outcomes of 154 valproate-exposed pregnancies (96.1% at least in the first trimester) were compared with those of 1315 pregnancies of women in the TIS database who were counselled for nonteratogenic exposures. The rate of major anomalies (some multiple) in the valproate group exposed in the first trimester was higher compared with controls after exclusion of genetic or cytogenetic anomalies (8 of 120 [6.7%] vs 31 of 1236 [2.5%], p = 0.018, relative risk [RR] = 2.66, 95% CI 1.25, 5.65). There were no cases of neural tube defect in the valproate-exposed group. Five of the eight major anomalies in the valproate group were cardiovascular, two of eight were mentally retarded, two of five male infants with major anomalies had hypospadias and three of eight were suspected of having fetal valproate syndrome. A daily dose > or =1000 mg was associated with the highest teratogenic risk (7 of 32 [21.9%] vs 31 of 1236 [2.5%], RR = 8.72, 95% CI 4.16, 18.30). In the subgroup exposed to polytherapy there was a 4-fold increase in the rate of major anomalies compared with controls. All major anomalies were in the group treated for epilepsy.

CONCLUSION

When valproate treatment cannot be avoided in the first trimester of pregnancy, the lowest effective dose should be prescribed, preferably as monotherapy, to minimize its teratogenic risk.

Neurodevelopmental delay in children exposed to antiepileptic drugs in utero: a critical review directed at structural study-bias

INTRODUCTION

The general issue whether in utero exposure to antiepileptic drugs (AEDs) causes congenital malformations (teratogenicity) was raised as early as 1968. The 'congenital hydantoin syndrome' after intrauterine exposure to phenytoin (PHT) was first described in 1975. In 1984, DiLiberti proposed the label 'Fetal Valproate Syndrome' (FVS) for children with a cluster of minor congenital anomalies in the form of dysmorphic facial appearances with or without major abnormalities after intra-uterine exposure to valproate (VPA). Later, also the presence of central nervous system (CNS) dysfunction became part of the description. The question whether developmental delay, educational impairment, or behavioural disorders are also a characteristic of intrauterine exposure to AEDs and especially VPA, is of major importance to many women with epilepsy, parents and physicians involved.

METHODS

Literature was searched using MEDLINE and other relevant databases: 56 studies were identified and interpreted.

RESULTS

The identified studies do not allow definite conclusions. The possibility of neurodevelopmental delay, behavioural disorders, or learning disabilities as an outcome of in utero exposure to AEDs and especially VPA, needs to be considered seriously. The literature however does not provide evidence for a valid risk estimate. Moreover the evidence found for a specific increased risk for VPA could be structurally biased.

DISCUSSION

The major problem in this field is the methodology and in particular the existence of important confounding factors that complicate any attempt to correlate intra-uterine exposure to AEDs with neurodevelopmental delay. We propose a number of guidelines for studies on behavioural teratogenicity.

Epilepsy in pregnancy

This article explores the therapeutic problems that arise when a patient with epilepsy on treatment becomes pregnant and needs both effective seizure control and attention to the safety of her fetus

Women with epilepsy: hormonal issues from menarche through menopause

Epilepsy is a multilayered disorder complicated by numerous comorbid conditions and hormonal changes. More than 1.5 million girls and women with epilepsy face side effects that are compounded at different ages by menstruation, fertility, pregnancy, fetal health, bone health, and other health issues. Changes in hormonal balance during maturation, from menarche through menopause, affect seizure thresholds and antiepileptic drugs, and vice versa. This overview provides physicians with a background on the multiple issues relevant to women of all ages in the reproductive years, including those planning to conceive and those who are pregnant, and beyond the childbearing years.

Unilateral multicystic dysplastic kidney in infants exposed to antiepileptic drugs during pregnancy

Prenatal exposure to antiepileptic drugs (AEDs) increases the risk of major congenital malformations (MCM) in the fetus. AED-related abnormalities include heart and neural tube defects, cleft palate, and urogenital abnormalities. Among the various congenital anomalies of the kidney and urinary tract (CAKUT), multicystic dysplastic kidney (MCDK) disease is one of the most severe expressions. Although prenatal ultrasound (US) examination has increased the prenatal diagnosis of MCDK, the pathogenesis is still unclear. We report on four cases of MCDK in infants of epileptic women treated with AEDs during pregnancy. From October 2003 to June 2006, we observed four infants with unilateral MCDK born to epileptic women. Three patients were considered to have typical features of multicystic dysplastic kidney, and one infant was operated because of a cystic pelvic mass in the absence of a kidney in the left flank. The macroscopic appearance of this mass showed an ectopic multicystic kidney confirmed by histological findings. All patients have been studied by US scans, voiding cystourethrogram (VCUG), and radionuclide screening isotope imaging. The prenatal exposure to AEDs increases the risk of major congenital malformations from the background risk of 1-2% to 4-9%. AEDs may determine a defect in apoptosis regulation that could lead to abnormal nephrogenesis, causing MCDK. Carbamazepine (CBZ) and phenobarbital (PHB) during pregnancy should be used at the lowest dosage compatible with maternal disease. The reduction, or even suspension, of drug dosage should be achieved from the periconceptional period to the first 8 weeks of gestation to avoid any interference with organogenesis.

A survey of antiepileptic prescribing to women of childbearing potential in psychiatry

Antiepileptic drugs (AEDs) are teratogenic. The aim of this survey was to ascertain whether clinicians followed recently published guidelines for prescribing AEDs to women of childbearing potential in England and Wales. We reviewed the case notes of all women aged 16-47 years who were initiated on valproate or carbamazapine in the psychiatric departments of three teaching hospitals over a 12 month period. Standards of documentation regarding childbearing issues in this representative sample were poor. The results are of concern given the widespread use of antiepileptic drugs in psychiatry.

In utero exposure to antiepileptic drugs: teratogenicity and neonatal morbidity

Clinical studies have extensively documented the various risks posed by in utero exposure to antiepileptic drugs (AEDs). However, it is difficult to sort out the extent to which any given AED is responsible for a particular outcome, given the disparities in patients taking the drugs, their type and severity of epilepsy, and the various possible AEDs, as well as the vast number of outcomes that could be assessed. This review focuses on AED exposure during pregnancy and how it affects the risks of neonatal morbidity and major congenital malformations.

Management of epilepsy in women of childbearing age: practical recommendations

Women with epilepsy should not be discouraged from becoming pregnant as the likelihood of having a healthy baby is very high. However, in such women, early and individualised counselling about pregnancy and contraception is essential. Ideally, pregnancies should be planned, folic acid (5 mg/day) given and antiepileptic drug (AED) treatment optimised well before conception to ensure that the lowest dosage that controls seizures is administered. When initiating AEDs in a woman of childbearing age, the most appropriate drug for the seizure type and syndrome should be chosen, although it is preferable to avoid valproate, because of a possible elevated risk of fetal malformations, when equi-effective agents are available for a given syndrome. In women who become pregnant while taking AEDs, fetal monitoring should include high-resolution ultrasonography before week 20 and measurement of serum alpha-fetoprotein levels. Amniocentesis is not routinely indicated. The measurement of blood concentrations of AEDs can be useful to ensure that the lowest possible maintenance dosage is being used, especially for those drugs whose pharmacokinetics are likely to change during pregnancy. Breastfeeding should be encouraged whatever the treatment administered.

Neuroteratogens in man: An overview with special emphasis on the teratogenicity of antiepileptic drugs in pregnancy

The most active growth and development of the human cerebrum and cerebellum occurs in the second half of pregnancy and in the first year of life. It is therefore not surprising that many teratogens may also affect development causing slight, moderate or even severe brain damage. The "classical" antiepileptic drugs (AEDs) valproic acid (VPA), phenytoin, phenobarbital, primidone and carbamazepine are all considered to be teratogenic. They may increase the rate of major congenital anomalies including neural tube defects (NTD), cause specific facial and other dysmorphic features--the "Anti Epileptic Drug Syndrome" (AEDS) and often some degree of mental impairment. Of these AEDs, the most teratogenic seems to be valproic acid, causing about 2% of NTD and an additional increase of 4-8% in major congenital anomalies. Phenytoin also increases the rate of various anomalies, but apparently not of NTD. Phenobarbital primidone and carbamazepine are also teratogenic and impair intellectual function but to a lesser extent than VPA and phenytoin. Cognition is mainly impaired in the children that also exhibit the AEDS. The impairment is slight to moderate, leaving the affected children with a close to borderline intelligence. Lamotrigine monotherapy in pregnancy seems to be relatively safe. In general, polytherapy is more dangerous to the fetus than monotherapy and, at least for VPA and lamotrigine, there seems to be a "threshold effect".

Valproic Acid in Epilepsy

Valproic acid (sodium valproate) is widely used as a first-line antiepileptic agent. As with many antiepileptic drugs, there are a number of consequences associated with the use of valproic acid in women of child-bearing potential. Most pregnancies have a favourable outcome in women with epilepsy, and these women should not be discouraged from becoming pregnant. Unlike many other antiepileptic drugs, valproic acid has no significant pharmacokinetic interactions with the steroid hormones used in oral contraceptives. During pregnancy, the major risks to mother and child result from loss of seizure control on the one hand, and an elevated risk of major congenital malformations due to antiepileptic drug treatment on the other. In particular, an elevated risk of major congenital malformations associated with valproic acid use has been a consistent finding in studies of patient registries and several large case series. In addition, developmental delay, characterised by low verbal IQ, has also been reported in children exposed to valproic acid in utero, although the relative risk is not precisely known. For these reasons, pregnancies in women being treated with valproic acid need to be planned, and the benefit-risk ratios associated with continuing valproic acid or changing treatment need to be discussed with the patient. When treatment with valproic acid is the most appropriate treatment to achieve optimal seizure control, a number of measures can be implemented to minimise risk to the fetus. These include the use of the lowest possible effective dose of valproic acid in monotherapy (ideally <1000 mg/day), appropriate folic acid supplementation and close antenatal monitoring. Regular counselling is a prerequisite for informed planning of pregnancies and optimisation of the probability of a healthy outcome. Future research on valproic acid and pregnancy should involve risk assessment in large, population-based prospective studies.

Birth defects after prenatal exposure to antiepileptic drugs

BACKGROUND

Exposure to antiepileptic drugs (AEDs) in the first trimester of pregnancy has been associated with an increased risk of major congenital anomalies (MCAs) in offspring. Most of the studies, however, have been fraught with methodological shortcomings, and differences in ascertainment methods and classifications prevent meaningful data pooling. Individual studies lacked the statistical power to assess comparative risks associated with specific AEDs.

RECENT DEVELOPMENTS

Several larger-scale studies, including collaborative multinational registries, have been set up to compare MCA risks associated with different treatments, including newer generation AEDs. Results have largely been consistent with the notion that monotherapy with the most commonly used AEDs is associated with an increase in risk of MCAs by two to three times, and that the magnitude of risk increases in offspring exposed to polytherapy. Available evidence does not suggest that epilepsy per se is associated with a major increase in the risk of MCAs. Almost all studies have suggested that exposure to valproic acid is associated with a greater incidence of MCAs than other AEDs. Valproic acid is also the only AED for which a dose-dependency has been confirmed in several studies: the increase in risk of MCAs, compared with other AEDs, is especially evident at doses above 800-1000 mg/day. Data from the North American registry have suggested that phenobarbital may also have a higher teratogenic risk compared with AEDs other than valproic acid, but evidence remains inconclusive. Information about effects on fetuses of newer generation AEDs other than lamotrigine and oxcarbazepine is scant. Although teratogenic effects of lamotrigine and oxcarbazepine have not been established with certainty, none of the investigations to date identified any statistically significant difference in rates of MCAs between infants exposed to lamotrigine or oxcarbazepine and infants exposed to carbamazepine. In the case of lamotrigine, moreover, a positive correlation between maternal dose and rates of MCAs has been identified. WHERE NEXT?: Collaborative pregnancy registries worldwide are at work to fill remaining gaps in knowledge. Issues to be addressed include the comparative risks associated with phenobarbital, with low-dose valproic acid, with newer generation AEDs, and with specific AED combinations; the influence of potential confounders; and the interaction of AED-associated risks with other risk factors, such as genetic profiles. Large scale studies may also clarify whether individual AEDs differ in their ability to cause specific anomalies. Finally, studies are urgently needed to investigate other potential adverse effects of AED exposure, with special reference to effects on postnatal intellectual development.

Management of epilepsy in women

There are many aspects to the management of epilepsy in women related to their role in reproduction. Some of these need to be considered in adolescents, some are related to pregnancy, concerning both the mother and her infant, and others with the menstrual cycle and the menopause. This review considers contraception, fertility, teratogenicity, and the use of folic acid. It also discusses the special investigations in pregnancy, hyperemesis, the effect of pregnancy on the control of epilepsy, the effect of seizures on the fetus, a first fit in pregnancy, pseudoseizures, seizures during delivery, vitamin K, breast feeding, postpartum maternal epilepsy, hereditary risks, counselling, catamenial epilepsy, the menopause, and bone density.

Teratogenicity of sodium valproate

The teratogenicity of the widely popular antiepileptic drug (AED) and mood stabiliser sodium valproate (also known as valproate, VPA) has been evidenced by previous research; however, these findings have often been limited by a small population sample of exposed women and a retrospective study design. Many factors contribute to the teratogenicity of VPA. These include the number of drugs that are co-administered, drug dosage, differences in maternal and/or infant metabolism, the gestational age of the fetus at exposure, and hereditary susceptibility. VPA has been associated with a variety of major and minor malformations, including a 20-fold increase in neural tube defects, cleft lip and palate, cardiovascular abnormalities, genitourinary defects, developmental delay, endocrinological disorders, limb defects, and autism. It has been suggested that polytherapy treatment in epileptic pregnant women increases the risk of teratogenicity in offspring. Furthermore, there is an established relationship between VPA dose and adverse outcome. Large single doses of VPA potentially cause high peak levels in the fetal serum resulting in deleterious effects. Currently there is an increase in the number of national and international pregnancy registries being formed in an effort to better identify the teratogenic effects of AEDs. These efforts hope to enhance our understanding of AEDs and their associated risks by addressing past study limitations.

Teratogenicity of antiepileptic drugs: state of the art: review

PURPOSE OF REVIEW

Information on the risks associated with antiepileptic drug (AED) use in pregnancy is necessary for a rational approach to the management of women of childbearing potential who have epilepsy. This reviews addresses recent reports on the risk for birth defects and impaired postnatal development attributable to prenatal exposure to AEDs.

RECENT FINDINGS

Some studies have indicated greater risk for birth defects as well as for lower verbal IQ in association with exposure to valproic acid, as compared with some other AEDs. The risk appears to be greater at doses above 800-1000 mg/day; lower doses may not carry higher risks than those associated with other AEDs. This observation is a cause of concern but more data are needed from prospective studies to assess the possible impact of confounding factors in order to clarify whether there is a causal relationship. Large-scale pregnancy registries have been launched and are expected to provide more conclusive comparative data on the most frequently used AEDs in the near future.

SUMMARY

Although further studies are needed, it appears reasonable to use valproic acid with caution in women with epilepsy who are planning to become pregnant, and to consider prescribing other equally effective and safer AEDs if they are available. The importance of seizure control during pregnancy must not be neglected, and any attempt to change treatment should be done before conception. Drug withdrawal during pregnancy should be avoided, and patients should be made aware that definitive evidence on the relative safety of AEDs is lacking.

Using current evidence in selecting antiepileptic drugs for use during pregnancy

Children born to mothers taking antiepileptic drugs (AEDs) are at increased risk for findings of fetal anticonvulsant syndrome. Accepted treatment paradigms to minimize fetal risks include use of AED monotherapy and folic acid supplementation. However, as data are acquired from several ongoing pregnancy registries, differential risks among the various AED monotherapy regimens are being defined, further improving fetal outcomes.