Valproate and the risk for congenital malformations: Is formulation and dosage regime important?

BackgroundUse of valproate in pregnancy, especially in doses over 1000 mg a day, is known to be associated with a higher risk for major congenital malformations compared with other antiepileptic drugs. We sought to investigate whether the increased risk could be minimised by using controlled release or divided daily doses of valproate.MethodsThe UK Epilepsy and Pregnancy Register is a prospective, observational and follow up study set up to determine the risks of major congenital malformations for infants exposed to antiepileptic drugs in utero. In this study we have extracted data for those pregnancies exposed to valproate in monotherapy. We have calculated malformation rates and relative risks as a function of valproate exposure.ResultsOutcome data were available for 1109 pregnancies exposed to valproate in monotherapy. Exposure to 1000 mg a day or more of valproate was associated with almost double the risk of major congenital malformation compared with daily valproate doses below 1000 mg daily (8.86% vs 4.88%, RR: 1.7; 95% CI: 1.1–2.9). There were no differences in the risks for malformations between standard release valproate and controlled release valproate preparations (RR: 1.11; 95% CI: 0.67–1.83) or for those exposed to single or multiple daily administrations (RR: 0.99, 95% CI: 0.58–1.70).ConclusionPrescribing controlled release valproate or multiple daily administrations in pregnancy did not reduce the risk for malformations. Higher malformation rates observed with in utero exposure to valproate are more likely related to total daily dose, rather than peak serum levels.     

Is carbamazepine a human teratogen?

The foetal outcomes of 2,635 pregnancies recorded in the Australian Pregnancy Register were studied. In at least the initial 4 months of 515 pregnancies, there had been no intrauterine exposure to antiepileptic drugs, though the women involved in 264 of these pregnancies took antiepileptic drugs in later pregnancies. Compared with these 515 drug-unexposed pregnancies, foetal malformations risks were increased more than five-fold in association with valproate monotherapy, and more than doubled in association with carbamazepine monotherapy (p < 0.05). There were no statistically significant increases in malformation rates associated with other more commonly used antiepileptic drugs, while the malformation risk in relation to levetiracetam exposure was lower than that in the drug-unexposed pregnancies. The published literature has rather consistently shown raised malformation rates associated with carbamazepine monotherapy, though only once was it statistically significant. There now appears to be enough evidence to make it likely that carbamazepine possesses some teratogenic capacity. This makes it unwise to employ the malformation rate associated with carbamazepine monotherapy as a comparator when assessing the foetal hazards from exposure to newer antiepileptic drugs. Levetiracetam may prove a better comparator if adequate untreated control material is unobtainable.     

The teratogenic risk of antiepileptic drug polytherapy

Purpose: To compare the risks of fetal malformation during pregnancy associated with antiepileptic drug (AED) polytherapy and monotherapy. Methods: Statistical analysis of malformation rate and antiepileptic drug exposure data from the Australian Register of Antiepileptic Drugs in Pregnancy, and from the literature. Results: The calculated relative risk (RR) value for AED polytherapy compared with monotherapy was below 1.0 in only 3 of 14 literature publications. In the register, at 1 year postnatally there were fetal malformations in 5.32% of 282 AED polytherapy pregnancies, and in 7.84% of 791 AED monotherapy pregnancies, an RR of 0.68 [95% confidence interval (CI) 0.39–1.17). For pregnancies exposed to valproate, the RR of fetal malformation (0.39, 95% CI 0.20–0.89) was lower in polytherapy (7.26%) than in monotherapy (17.9%); the difference did not depend on valproate dosage. The RR values for fetal malformation were not significantly different for AED polytherapy and monotherapy when valproate was not involved. Logistic regression suggested that coadministration of lamotrigine may have reduced the malformation risk from valproate. Discussion: The fetal hazard of AED polytherapy relative to monotherapy may depend more on the degree of exposure to valproate than on the fact of polytherapy per se. Coadministration with lamotrigine may lower the fetal risk of valproate therapy.     

Recurrence risk of congenital malformations in infants exposed to antiepileptic drugs in utero

Purpose: Use of antiepileptic drugs in pregnancy is associated with congenital malformations and developmental delay. Previous studies have suggested that women who have had one child with a congenital malformation are at increased risk of having other children with malformations. We sought to confirm the magnitude of risk in a large cohort drawn from the United Kingdom Epilepsy and Pregnancy Register. Methods: The United Kingdom Epilepsy and Pregnancy Register is a prospective, observational registration and follow‐up study set up to determine the relative safety of antiepileptic drugs in pregnancy. We have extracted data for those women who prospectively registered more than one pregnancy and calculated the recurrence risks for fetal malformations. Key Findings: Outcome data were available for 1,534 pregnancies born to 719 mothers. For women whose first child had a congenital malformation there was a 16.8% risk of having another child with a congenital malformation, compared with 9.8% for women whose first child did not have a malformation (relative risk 1.73, 95% confidence interval [CI] 1.01–2.96). The risk for recurrence was 50% for women who had had two previous children with a congenital malformation. There was a trend toward a higher risk for recurrent malformations in pregnancies exposed to valproate (21.9%, relative risk 1.47, 95% CI 0.68–3.20) and topiramate (50%, relative risk 4.50, 95% CI 0.97–20.82), but not for other drugs such as carbamazepine and lamotrigine. Recurrence risks were also higher for pregnancies exposed to polytherapy regimens and for those where the dose of antiepileptic drug treatment had been increased after the first pregnancy. Significance: Women who have had a child with a malformation are at increased risk of having other children with malformations. This is in keeping with previous reports that have suggested that genetic influences may be one of the factors determining the teratogenic risk of antiepileptic drugs.     

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.     

The internal control group in a register of antiepileptic drug use in pregnancy.

The aim of this study was to determine how valid 68 first-trimester pregnancies of untreated epileptic women would prove as an internal control group for investigating foetal malformation rates in 709 simultaneously collected antiepileptic drug-exposed pregnancies in an Australian register of pregnancies in epileptic women. We carried out comparisons of values for parameters relating to personal details, obstetric aspects, and epilepsies prior to and during pregnancy in the drug-exposed and drug-unexposed pregnancies, with observations on subpopulations within the drug-unexposed group. Statistically significant (p<0.05) differences existed for only seven of more than 50 parameters compared. None of these seven parameters had a statistically significant influence on foetal malformation rates in the whole dataset. In 23 of the 65 epileptic pregnancies unexposed to antiepileptic drugs, therapy had been ceased shortly prior to pregnancy and was often resumed after the first trimester. In the remaining 42, therapy had been ceased earlier, often despite continuing seizures. Planned withdrawal of therapy did not appear to produce additional hazards for mothers and foetuses in the former subgroup. In the data collection studied, there did not appear to be evidence of statistically significant differences between untreated pregnancies and treated epileptic pregnancies that would be likely to invalidate the former group as an internal control for the latter, at least when assessing foetal malformation rates.     

Malformation risks of antiepileptic drugs in pregnancy: a prospective study from the UK Epilepsy and Pregnancy Register

OBJECTIVE: To assess the relative risk of major congenital malformation (MCM) from in utero exposure to antiepileptic drug (AEDs). METHODS: Prospective data collected by the UK Epilepsy and Pregnancy Register were analysed. The presence of MCMs recorded within the first three months of life was the main outcome measure. RESULTS: Full outcome data were collected on 3607 cases. The overall MCM rate for all AED exposed cases was 4.2% (95% confidence interval (CI), 3.6% to 5.0%). The MCM rate was higher for polytherapy (6.0%) (n = 770) than for monotherapy (3.7%) (n = 2598) (crude odds ratio (OR) = 1.63 (p = 0.010), adjusted OR = 1.83 (p = 0.002)). The MCM rate for women with epilepsy who had not taken AEDs during pregnancy (n = 239) was 3.5% (1.8% to 6.8%). The MCM rate was greater for pregnancies exposed only to valproate (6.2% (95% CI, 4.6% to 8.2%) than only to carbamazepine (2.2% (1.4% to 3.4%) (OR = 2.78 (p<0.001); adjusted OR = 2.97 (p<0.001)). There were fewer MCMs for pregnancies exposed only to lamotrigine than only to valproate. A positive dose response for MCMs was found for lamotrigine (p = 0.006). Polytherapy combinations containing valproate carried a higher risk of MCM than combinations not containing valproate (OR = 2.49 (1.31 to 4.70)). CONCLUSIONS: Only 4.2% of live births to women with epilepsy had an MCM. The MCM rate for polytherapy exposure was greater than for monotherapy exposure. Polytherapy regimens containing valproate had significantly more MCMs than those not containing valproate. For monotherapy exposures, carbamazepine was associated with the lowest risk of MCM.     

Teratogenicity of antiepileptic drug combinations with special emphasis on epoxidation (of carbamazepine)

A higher rate of congenital anomalies has been found after prenatal exposure to some combinations of antiepileptic drugs than to the separate drugs. In an earlier study a rate of 58% congenital anomalies was found among infants exposed to carbamazepine plus phenobarbitone plus valproate. In this study an attempt was made to determine whether this specific combination of drugs has teratogenic activity due to metabolic interaction. The epidemiological data were analyzed further. The high rate of congenital anomalies after prenatal exposure to this combination could not be explained by the effects of one or two of these drugs only, nor by additional exposure to phenytoin. Assuming that metabolic interaction in the arene oxide pathway resulting in accumulation of epoxide intermediates of antiepileptic drugs could be responsible for teratogenesis, the ratio of carbamazepine to carbamazepine-10, 11-epoxide concentrations in serum was determined in adult patients with epilepsy who were treated with carbamazepine only and with different combinations of phenobarbitone, valproate, and/or phenytoin. For carbamazepine monotherapy the mean ratio was 8.19. For all combinations lower ratios were found, indicating accumulation of carbamazepine-10,11-epoxide. The combination of carbamazepine, phenobarbitone, valproate, and phenytoin showed the lowest ratio (1.94), followed by carbamazepine, valproate, and phenytoin and by carbamazepine, phenobarbitone, and valproate (2.81 and 3.18, respectively). These results give rise to the question of whether the combination of carbamazepine, phenobarbitone, valproate, and/or phenytoin has teratogenic activity by accumulation of carbamazepine-10,11-epoxide or other epoxide intermediates, and stress the need to take metabolic interactions into account when investigating the teratogenic activity of antiepileptic drugs.     

Teratogenicity of Antiepileptic Drugs: Analysis of Possible Risk Factors

To determine the primary factors responsible for the increased incidence of malformation in the off-spring of antiepileptic drug (AED)-treated epileptic mothers, special attention was paid to drug combinations in a prospective study of 172 deliveries. Variables used for analysis were eight antiepileptic drugs (AEDs) and total daily dosages (drug score), and seven background factors consisting of maternal age at delivery, gravida, outcome of previous pregnancy, etiology and type of epilepsy, occurrence of seizures in the first trimester of pregnancy, and seizure frequency during pregnancy. The overall rate of malformation was 14.0%. Thirty-one patients were administered a single drug, and the rate of malformation was 6.5%. The remaining 141 patients were treated with multiple AEDs, and the rate of malformation was 15.6%. The drug score of the latter group was significantly higher than the former (p = 0.01). There was no definite dose-dependent increase in the incidence of malformations associated with any individual AEDs. There was no relationship between the type of defect and individual AEDs. Wilcoxon rank-sum test revealed significant association between the drug score, valproate (VPA), and congenital malformation. Carbamazepine (CBZ) also reached an almost significant level. Furthermore, VPA polypharmacy produced the highest incidence of malformation, higher than that produced by any other AED or drug combination. There was no significant association between the presence of malformations and the other putative risk factors. These results suggest that high dose of AEDs reflecting polypharmacy, VPA polypharmacy in particular, are primary factors responsible for the increased incidence of congenital malformation in the offspring of treated epileptic mothers.     

Epilepsy therapy: issues for women and men

It has been suggested that polycystic ovary syndrome is a common finding in women treated with valproate. However, in a recent study this suggestion could not be confirmed. There is currently no clear evidence that valproate contributes to the development of the polycystic ovary syndrome. Focal epileptic discharges may have an impact on the hypothalamic-pituitary-ovarian or -testicular axis. In the case of successful epilepsy surgery the impact of epilepsy on endocrine functioning may cease. This may lead to a normalization of disturbed menstrual cycles in women, and leads to a post-surgical increase of serum androgens in men. Both findings are supplemented by the results of animal experiments. Children exposed to antiepileptic drugs during pregnancy show a normal psychomotor and cognitive development. However, newly developed as well as traditional antiepileptic drugs increase the risk that a child exposed to these drugs during pregnancy will develop a malformation.     

Critical relationship between sodium valproate dose and human teratogenicity: results of the Australian register of anti-epileptic drugs in pregnancy

To compare the incidence of foetal malformations (FMs) in pregnant women with epilepsy treated with different anti-epileptic drugs (AED) and doses, and the influence of seizures, family and personal history, and environmental factors. A prospective, observational, community-based cohort study. METHODS: A voluntary, Australia-wide, telephone-interview-based register prospectively enrolling three groups of pregnant women: taking AEDs for epilepsy; with epilepsy not taking AEDs; taking AEDs for a non-epileptic indication. Four hundred and fifty eligible women were enrolled over 40 months. Three hundred and ninety six pregnancies had been completed, with 7 sets of twins, for a total of 403 pregnancy outcomes. RESULTS: 354 (87.8%) pregnancy outcomes resulted in a healthy live birth, 26 (6.5%) had a FM, 4 (1%) a death in utero, 1 (0.2%) a premature labour with stillbirth, 14 (3.5%) a spontaneous abortion and 4 lost to follow-up. The FM rate was greater in pregnancies exposed to sodium valproate (VPA) in the first trimester (16.0%) compared with those exposed to all other AEDs (16.0% vs. 2.4%, P < 0.01) or no AEDs (16.0% vs. 3.1%, [Formula: see text] ). The mean daily dose of VPA taken in pregnancy with FMs was significantly greater than in those without (1,975 vs. 1,128 mg, P < 0.01). The incidence of FM with VPA doses >or= 1,100 mg was 30.2% vs. 3.2% with doses <1,100 mg (P <0.01). CONCLUSIONS: There is a dose-effect relationship for FM and exposure to VPA during the first trimester of pregnancy, with higher doses of VPA associated with a significantly greater risk than with lower doses or with other AEDs. These results highlight the need to limit, where possible, the dose of VPA in pregnancy.     

Is lamotrigine a significant human teratogen? Observations from the Australian Pregnancy Register

Lamotrigine (LTG) is increasingly being prescribed in pregnancy for women with epilepsy in place of valproate (VPA), because of the teratogenic risks associated with the latter. It is therefore important to know the teratogenic hazard associated with LTG, relative to VPA and to other commonly used antiepileptic drugs (AEDs). Data from the Australian Register of Antiepileptic Drugs in Pregnancy was examined to determine the incidence of teratogenicity determined 1 year from completion of pregnancy in women who took AEDs in monotherapy during pregnancy. Compared with a 3.4% malformation incidence in women who took no AEDs (N = 118), the incidences for LTG (N = 243), carbamazepine (CBZ) (N = 302) and VPA (N = 224) were, respectively, 4.9%, 5.3% and 15.2%, the latter statistically significantly greater than the risk for no AED therapy in pregnant women with epilepsy. Logistic regression analysis showed no tendency for foetal hazard to increase with increasing LTG dose in pregnancy, unlike the situation for VPA. However, seizure control in pregnancy tended to be not as good in the women taking LTG compared with those taking VPA, though the data examined were not adequate to permit definite conclusions regarding this matter. We conclude that LTG monotherapy in pregnancy is safer than valproate monotherapy from the point of view of foetal malformations, and no more hazardous in this regard than therapy with other commonly used AEDs.     

Teratogenicity of the newer antiepileptic drugs - the Australian experience

Data on the use in pregnancy of the new antiepileptic drugs (AED) are limited. We analysed data collected by the Australian Pregnancy Register to provide information on their relative teratogenicity. The database containing pregnancy outcomes from 1317 women with epilepsy (WWE) was examined for three widely used new AED in monotherapy in the first trimester - lamotrigine, levetiracetam and topiramate. This was compared with outcomes of pregnant WWE on monotherapy with three traditional AED, and with untreated women. The incidence of malformations associated with lamotrigine monotherapy was 12/231 (5.2%), with topiramate 1/31 (3.2%) and with levetiracetam 0/22 (0%). This compares with rates of 1/35 (2.9%) for phenytoin, 35/215 (16.3%) for valproate (VPA), 19/301 (6.3%) for carbamazepine and 6/116 (5.2%) for untreated women. There was no evidence of dose-dependent risks of foetal malformation, except with VPA monotherapy. We conclude that the new AED appear no more teratogenic than traditional drugs in monotherapy.     

Navigating toward fetal and maternal health: the challenge of treating epilepsy in pregnancy

A rational approach to the treatment of women of childbearing potential with epilepsy has been hampered by the lack of conclusive data on the comparative teratogenic potential of different antiepileptic drugs (AEDs). Although, several cohort studies on birth defects associated with AED use during pregnancy have been published, these have generally failed to demonstrate differences in malformation rates between AEDs, probably mainly due to insufficient power. In particular, pregnancies with new generation AEDs have been too few. In recent years, pregnancy registries have been introduced to overcome this problem--EURAP (an international collaboration), the North American, and the U.K. AED and pregnancy registries are observational studies that prospectively assess pregnancy outcome after AED exposure using slightly different methods. Each has enlisted 3-5,000 pregnancies in women with epilepsy, and the North American and the U.K. have released preliminary observations. Thus the U.K. registry reported a higher malformation rate with valproate, 5.9% (4.3-8.2%; 95% CI), than with carbamazepine, 2.3% (1.4-3.7%), and lamotrigine, 2.1% (1.0-4.0%). Most of the more recent cohort studies have also identified a nonsignificant trend toward a higher teratogenicity with valproate. These signals need to be interpreted with some caution since none of the studies to date have fully assessed the impact of possible confounders, such as type of epilepsy, family history of birth defects, etc. However, with increasing number of pregnancies it should be possible in the near future for the pregnancy registries to take such confounding factors into account and thus make more reliable assessments of the causal relationship between exposure to specific AEDs and teratogenic risks. While awaiting more conclusive results, it appears reasonable to be cautious in prescribing valproate to women considering to become pregnant if other suitable treatment alternatives, and with less teratogenic potential, are available. Any attempt to change treatment should, however, be accomplished well before conception. The importance of maintained seizure control must also be kept in mind, and the woman who needs valproate to control her seizures should not be discouraged from pregnancy, provided that counseling at the best of available knowledge is given.     

The effects of valproate exposure in utero on behavior and the need for educational support in school-aged children

Children exposed to valproate monotherapy in utero were evaluated with respect to neurological functioning, behavior, and additional educational needs, and the results were compared with those for age- and gender-matched controls exposed to carbamazepine and children with no prenatal exposure to antiepileptic drugs. We identified from the community-based pregnancy registry of Kuopio University Hospital area (1989–2000) all first-born and school-aged children exposed to valproate (N = 13). Neurological and neuropsychological assessments were made clinically, and behavioral problems were assessed with the Conners’ Teacher Rating Scale (CTRS). Eight children (62%) exposed to valproate and two (15%) each in the carbamazepine-exposed and nonexposed groups (P = 0.022) required educational support. Minor dysmorphic features were noted in eight children (62%) exposed to valproate and in three children (23%) each in the carbamazepine-exposed and nonexposed groups. On CTRS, children exposed to valproate received higher scores, indicating behavioral problems. In our small but population-based study, all children exposed to valproate had minor, and some of them major, cognitive or neurological problems. This difference is clearly observed when assessing each child individually, but the many confounding factors explaining at least part of this difference are difficult to control and avoid in clinical practice. Larger studies with a prospective design are needed to confirm these findings.     

Outcome of pregnancy in women attending an outpatient epilepsy clinic: adverse features associated with higher doses of sodium valproate

The risk of an adverse outcome to pregnancy is increased in women with epilepsy. This is partly attributable to antiepileptic drugs. Guidelines for the management of pregnancy in women with epilepsy generally advise against polytherapy but make no distinction between the risks of different drugs. Several recent studies have however shown greater risk of adverse outcome in offspring exposed to sodium valproate in utero, particularly at higher doses. The outcome of pregnancy was monitored to identify antiepileptic drug treatment associated with a poor outcome in a mainly prospective study of women attending an outpatient clinic. From January 1990 to December 1999 all 69 pregnancies in women referred to the clinic were monitored. Drug treatments and other risk factors were recorded. In each child dysmorphic features, developmental delay and structural anomalies were assessed and graded. Data were analysed for drug- and dosage-dependent differences in outcome. In each assessment area a positive association between adverse outcome and dose was found for sodium valproate but not for carbamazepine. Severe adverse outcomes were found only in children exposed to sodium valproate at maternal doses above 1000 mg per day.     

Epilepsia y gestación. Factores asociados con la presencia de crisis en la gestación

IntroductionThe management of epilepsy during pregnancy requires optimal seizure control, avoiding the potential teratogenic effects of antiepileptic drugs.ObjectivesThis study aims to describe the clinical characteristics and perinatal outcomes of pregnant patients with epilepsy; to analyse the factors associated with seizures during pregnancy; to describe the most commonly used antiepileptic drugs in these patients; and to analyse changes in treatment regimens in 2 periods, 2000-2010 and 2011-2018.MethodsWe conducted a prospective observational study of patients with epilepsy who reported their pregnancy between 2000 and 2018. Patients were evaluated in the first and second trimesters of pregnancy, after delivery, and at one year. Data were collected on demographic variables, epilepsy, and perinatal and obstetric variables.ResultsA total of 101 pregnancies were included. Patients’ mean age was 32.6 years; 55.4% had focal epilepsy, 38.6% had generalised epilepsy, and 5.9% had undetermined epilepsy. We recorded 90 live births, 9 miscarriages, and 5 cases of congenital malformations, 4 of which were born to women who received valproate monotherapy. Forty patients (39.6%) presented seizures, with 16 (40%) presenting generalised tonic-clonic seizures. The variables associated with seizures during pregnancy were poor seizure control in the year prior to pregnancy (66.7% vs. 15.1%; P < .001), treatment with 2 or more antiepileptic drugs (30% vs. 14.8%; P < .001), and untreated epilepsy (25% vs. 0%; P < .001). The antiepileptic drugs most widely used in monotherapy were lamotrigine (n = 19; 27.1%), valproate (n = 17; 24.2%), and levetiracetam (n = 12; 17.1%). In the most recent period (2011-2018), we observed a greater proportion patients receiving monotherapy (81.5%, vs. 55.3%), as well as a decrease in the use of carbamazepine (2.3%, vs. 23.1%) and valproate (20.5%, vs. 30.8%); and a marked increase in the use of levetiracetam (27.3%, vs. 0%).ConclusionsThe factors associated with the presence of seizures during pregnancy were previous poor seizure control, treatment with 2 or more antiepileptic drugs, and lack of treatment during pregnancy. The most commonly used drugs were lamotrigine, valproate, and levetiracetam, with an increase in levetiracetam use and a decrease in valproate use being observed in the later period (2011-2018).     

The effects of valproate exposure in utero on behavior and the need for educational support in school-aged children

Children exposed to valproate monotherapy in utero were evaluated with respect to neurological functioning, behavior, and additional educational needs, and the results were compared with those for age- and gender-matched controls exposed to carbamazepine and children with no prenatal exposure to antiepileptic drugs. We identified from the community-based pregnancy registry of Kuopio University Hospital area (1989-2000) all first-born and school-aged children exposed to valproate (N=13). Neurological and neuropsychological assessments were made clinically, and behavioral problems were assessed with the Conners' Teacher Rating Scale (CTRS). Eight children (62%) exposed to valproate and two (15%) each in the carbamazepine-exposed and nonexposed groups (P=0.022) required educational support. Minor dysmorphic features were noted in eight children (62%) exposed to valproate and in three children (23%) each in the carbamazepine-exposed and nonexposed groups. On CTRS, children exposed to valproate received higher scores, indicating behavioral problems. In our small but population-based study, all children exposed to valproate had minor, and some of them major, cognitive or neurological problems. This difference is clearly observed when assessing each child individually, but the many confounding factors explaining at least part of this difference are difficult to control and avoid in clinical practice. Larger studies with a prospective design are needed to confirm these findings.     

Oxcarbazepine in pregnancy: clinical experience in Argentina

The potential teratogenicity of antiepileptic drugs (AEDs) is a major concern for women with epilepsy who are considering pregnancy. Traditional AEDs are associated with an at least twofold risk of fetal malformations compared with the general population. The risk of malformations with newer AEDs is unclear. This article reports the multicenter clinical experience in Argentina of pregnant women with epilepsy receiving AEDs. Of 114 pregnancies monitored, 16 newborns had anomalies: 3 cardiac, 3 skull, and 2 gastrointestinal malformations, and 8 facial dysmorphies. Most fetal anomalies were observed following exposure to phenobarbital, valproate, and carbamazepine. Of 55 babies exposed to the new-generation AED oxcarbazepine (20 as combination therapy and 35 as monotherapy), one malformation (cardiac) was reported (in a patient receiving oxcarbazepine and phenobarbital). Thus, newer AEDs may have a lower teratogenic risk than traditional AEDs. These data add to the growing experience with AED therapy in pregnant women with 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.