Rebecca L. Bromley

AUTISM SPECTRUM DISORDERS FOLLOWING IN UTERO EXPOSURE TO ANTIEPILEPTIC DRUGS

There is evidence that in utero exposure to teratogenic substances such as thalidomide and alcohol may increase the risk of developing autism spectrum disorder (ASD)1 and that prenatal development may be a critical time. Animal model, case study, and retrospective reports have demonstrated that exposure to antiepileptic drugs (AEDs) in utero may also carry an increased risk for the development of ASD.2–5 ### Methods. The Liverpool and Manchester Neurodevelopment group is currently undertaking a prospective study to investigate the effects of exposure to AEDs in utero. Between 2000 and 2006, 620 women were recruited from antenatal clinics in both Liverpool and Manchester. Information has been collected on 632 live births; 296 births were to women with epilepsy (including 6 twin pairs), 249 of whom were exposed to AEDs at the beginning of gestation. Within the exposed group, 64 children were exposed to sodium valproate (VPA), 44 to lamotrigine (LTG), 76 to carbamazepine (CBZ), 14 to other monotherapy treatments, and 51 to polytherapy treatments. The remaining 47 births were to women with epilepsy who were not on medication. In addition, information has been collected on 336 live births (including two twin pairs) born to women without epilepsy who were not …

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.

Effects of fetal antiepileptic drug exposure: Outcomes at age 4.5 years

Objective: To examine outcomes at age 4.5 years and compare to earlier ages in children with fetal antiepileptic drug (AED) exposure. Methods: The NEAD Study is an ongoing prospective observational multicenter study, which enrolled pregnant women with epilepsy on AED monotherapy (1999–2004) to determine if differential long-term neurodevelopmental effects exist across 4 commonly used AEDs (carbamazepine, lamotrigine, phenytoin, or valproate). The primary outcome is IQ at 6 years of age. Planned analyses were conducted using Bayley Scales of Infant Development (BSID at age 2) and Differential Ability Scale (IQ at ages 3 and 4.5). Results: Multivariate intent-to-treat (n = 310) and completer (n = 209) analyses of age 4.5 IQ revealed significant effects for AED group. IQ for children exposed to valproate was lower than each other AED. Adjusted means (95% confidence intervals) were carbamazepine 106 (102–109), lamotrigine 106 (102–109), phenytoin 105 (102–109), valproate 96 (91–100). IQ was negatively associated with valproate dose, but not other AEDs. Maternal IQ correlated with child IQ for children exposed to the other AEDs, but not valproate. Age 4.5 IQ correlated with age 2 BSID and age 3 IQ. Frequency of marked intellectual impairment diminished with age except for valproate (10% with IQ <70 at 4.5 years). Verbal abilities were impaired for all 4 AED groups compared to nonverbal skills. Conclusions: Adverse cognitive effects of fetal valproate exposure persist to 4.5 years and are related to performances at earlier ages. Verbal abilities may be impaired by commonly used AEDs. Additional research is needed.

Breastfeeding in Children of Women Taking Antiepileptic Drugs: Cognitive Outcomes at Age 6 Years

IMPORTANCE Breastfeeding is known to have beneficial effects, but concern exists that breastfeeding during maternal antiepileptic drug (AED) therapy may be harmful. We previously noted no adverse effects of breastfeeding associated with AED use on IQ at age 3 years, but IQ at age 6 years is more predictive of school performance and adult abilities. OBJECTIVES To examine the effects of AED exposure via breastfeeding on cognitive functions at age 6 years. DESIGN, SETTING, AND PARTICIPANTS Prospective observational multicenter study of long-term neurodevelopmental effects of AED use. Pregnant women with epilepsy receiving monotherapy (ie, carbamazepine, lamotrigine, phenytoin, or valproate) were enrolled from October 14, 1999, through April 14, 2004, in the United States and the United Kingdom. At age 6 years, 181 children were assessed for whom we had both breastfeeding and IQ data. All mothers in this analysis continued taking the drug after delivery. MAIN OUTCOMES AND MEASURES Differential Ability Scales IQ was the primary outcome. Secondary measures included measures of verbal, nonverbal, memory, and executive functions. For our primary analysis, we used a linear regression model with IQ at age 6 years as the dependent variable, comparing children who breastfed with those who did not. Similar secondary analyses were performed for the other cognitive measures. RESULTS In total, 42.9% of children were breastfed a mean of 7.2 months. Breastfeeding rates and duration did not differ across drug groups. The IQ at age 6 years was related to drug group (P < .001 [adjusted IQ worse by 7-13 IQ points for valproate compared to other drugs]), drug dosage (regression coefficient, -0.1; 95% CI, -0.2 to 0.0; P = .01 [higher dosage worse]), maternal IQ (regression coefficient, 0.2; 95% CI, 0.0 to 0.4; P = .01 [higher child IQ with higher maternal IQ]), periconception folate use (adjusted IQ 6 [95% CI, 2-10] points higher for folate, P = .005), and breastfeeding (adjusted IQ 4 [95% CI, 0-8] points higher for breastfeeding, P = .045). For the other cognitive domains, only verbal abilities differed between the breastfed and nonbreastfed groups (adjusted verbal index 4 [95% CI, 0-7] points higher for breastfed children, P = .03). CONCLUSIONS AND RELEVANCE No adverse effects of AED exposure via breast milk were observed at age 6 years, consistent with another recent study at age 3 years. In our study, breastfed children exhibited higher IQ and enhanced verbal abilities. Additional studies are needed to fully delineate the effects of all AEDs. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00021866.

Cognition in school-age children exposed to levetiracetam, topiramate, or sodium valproate

Objective: To investigate the effects of prenatal exposure to monotherapy levetiracetam, topiramate, and valproate on child cognitive functioning. Methods: This was a cross-sectional observational study. Children exposed to monotherapy levetiracetam (n = 42), topiramate (n = 27), or valproate (n = 47) and a group of children born to women who had untreated epilepsy (n = 55) were enrolled retrospectively from the UK Epilepsy and Pregnancy Register. Assessor-blinded neuropsychological assessments were conducted between 5 and 9 years of age. Information was collected on demographic and health variables and adjusted for in multiple regression analyses. Results: In the adjusted analyses, prenatal exposure to levetiracetam and topiramate were not found to be associated with reductions in child cognitive abilities, and adverse outcomes were not associated with increasing dose. Increasing dose of valproate, however, was associated with poorer full-scale IQ (−10.6, 95% confidence interval [CI] −16.3 to −5.0, p < 0.001), verbal abilities (−11.2, 95% CI −16.8 to −5.5, p < 0.001), nonverbal abilities (−11.1, 95% CI −17.3 to −4.9, p < 0.001), and expressive language ability (−2.3, 95% CI −3.4 to −1.6, p < 0.001). Comparisons across medications revealed poorer performance for children exposed to higher doses of valproate in comparison to children exposed to higher doses of levetiracetam or topiramate. Conclusions: Preconception counseling should include discussion of neurodevelopmental outcomes for specific treatments and their doses and women should be made aware of the limited nature of the evidence base for newer antiepileptic drugs.

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.

The treatment of epilepsy in pregnancy:: The neurodevelopmental risks associated with exposure to antiepileptic drugs

A number of antiepileptic drugs (AEDs) have been confirmed as teratogens due to their association with an increased malformation rate. The majority of research to date does not find an association between prenatal exposure to monotherapy carbamazepine, lamotrigine or phenytoin and neurodevelopmental outcome in comparison to control children and noted higher abilities in comparison to children exposed to valproate; but further work is needed before conclusions can be drawn. Data for levetiracetam was limited to one study, as was the evidence for topiramate. Sodium valproate exposure appeared to carry a dose dependent risk to the developing brain, with evidence of reduced levels of IQ, poorer verbal abilities and increased rate of autistic spectrum disorder both in comparison to control children and children exposed to other AEDs. The severity of the neurodevelopmental deficits associated with prenatal exposure to valproate highlight the critical need to consider neurodevelopmental outcomes as a central aspect of teratological research.

In utero exposure to valproate increases the risk of isolated cleft palate

Introduction Orofacial clefting (OFC) has been described in infants exposed to valproic acid (VPA) prenatally, but often no distinction is made between cleft lip and palate (CLP) and isolated cleft palate (ICP). This distinction is important as these conditions have different management implications and the distinction has implications too for understanding the teratogenic mechanisms. Methods We searched EMBASE, Medline and Web of Science for observational studies describing OFC in association with VPA exposure. Searches for similarly exposed patients referred to a regional genetic centre and those recorded in the UK Epilepsy and Pregnancy Register (UKEPR) were undertaken. Cleft type and, where available, VPA doses prescribed were recorded. Results A total of 4459 cases of VPA exposure were reported in the literature in nine separate studies with 50 cases of OFC, the majority of which did not differentiate the cleft type. Eight patients ascertained through the regional genetic centre had ICP. Thirteen cases of OFC occurred in 1282 VPA monotherapy-exposed pregnancies in the UKEPR; nine had ICP and four had CLP, representing an 11.3-fold and 3.5-fold increase risk in ICP and CLP, respectively, over general population risk. Doses ranged from 200 to 2500 mg VPA daily with 73% of monotherapy ICP cases from the local cohort and UKEPR occurring at doses over 1000 mg. Conclusion ICP is the predominant cleft type seen in prenatal VPA exposure. Parents should be counselled appropriately and infants should undergo review after delivery for ICP. Pregnancy registers collecting information on congenital anomalies should make the distinction between CLP and ICP as the risk differs across the two conditions.

Does in utero exposure of antiepileptic drugs lead to failure to reach full cognitive potential

A clinical scenario of a young female on 800 mg of sodium valproate (VPA) who has recently failed lamotrigine (LTG) and levetiracetam (LEV) and who is currently planning a pregnancy is presented. Currently available data pertaining to the longer-term development of children exposed to antiepileptic drugs (AEDs) are reviewed along with considerations around the methodology and interpretation of such research. There is an accumulation of data highlighting significant risks associated with prenatal exposed to VPA, with the level of risk being mediated by dose. The majority of published evidence does not find a significant risk associated with carbamazepine (CBZ) exposure in utero for global cognitive abilities however the evidence for more specific cognitive skills are unclear. Limited data indicate that LTG may be a preferred treatment to VPA in terms of foetal outcome but further evidence is required. Too little data pertaining to LEV exposure is available and a lack of evidence regarding risk of this and other new AEDs should not be interpreted as evidence of safety.

Fetal antiepileptic drug exposure and cognitive outcomes

PURPOSE Data highlighting valproate as a human teratogen put in context the need to balance both maternal and fetal needs; maximising maternal health whilst minimising fetal risk. This led to increased research efforts to understand the associated risks with AED treatments. METHODS A review of currently published literature was undertaken. RESULTS In utero exposure to valproate was associated with a range of poorer neurodevelopmental outcomes when compared to control children and children exposed to other antiepileptic drugs (AEDs). Children exposed to carbamazepine were not found by the majority of studies to have poorer early development, although there is a lack of evidence regarding specific cognitive skills later in childhood and adolescence. Research regarding lamotrigine was limited to a small number of studies but suggests early global development or school aged IQ does not differ from control children, but less is known about specific cognitive skills. Evidence for the other AEDs including levetiracetam and topiramate were significantly limited. CONCLUSIONS Despite an improvement in momentum the evidence remains incomplete for neurodevelopmental outcomes and this limits evidence-based decision making. Further efforts are required to enhance the treatment of women by giving them the confidence that both the risks and the benefits of commonly used AEDs are known. Future research should also seek to increase our understanding of the children who experience neurodevelopmental difficulties in the context of exposure in the womb to AEDs and what interventions may be successful in maximising the outcome of these children.