Birth outcomes in women exposed to anticonvulsant drugs

Advances in Epidemiological Methods and Utilisation of Large Databases: A Methodological Review of Observational Studies on Central Nervous System Drug Use in Pregnancy and Central Nervous System Outcomes in Children

INTRODUCTION

Studies have used various epidemiological approaches to study associations between central nervous system (CNS) drug use in pregnancy and CNS outcomes in children. Studies have generally focused on clinical adverse effects, whereas variations in methodologies have not received sufficient attention.

OBJECTIVE

Our objective was to review the methodological characteristics of existing studies to identify any limitations and recommend further research.

METHODS

A systematic literature search was conducted on observational studies listed in PubMed from 1 January 1946 to 21 September 2017. Following independent screening and data extraction, we conducted a review addressing the trends of relevant studies, differences between various data sources, and methods used to address bias and confounders; we also conducted statistical analyses.

RESULTS

In total, 111 observational studies, 25 case-control studies, and 86 cohort studies were included in the review. Publications dating from 1978 to 2006 mainly focused on antiepileptic drugs, but research on antidepressants increased from 2007 onwards. Only one study focused on antipsychotic use during pregnancy. A total of 46 studies obtained data from an administrative database/registry, 20 from ad hoc disease registries, and 41 from ad hoc clinical samples. Most studies (58%) adjusted the confounding factors using general adjustment, whereas only a few studies used advanced methods such as sibling-matched models and propensity score methods; 42 articles used univariate analyses and 69 conducted multivariable regression analyses.

CONCLUSION

Multiple factors, including different study designs and data sources, have led to inconsistent findings in associations between CNS drug use in pregnancy and CNS outcomes in children. Researchers should allow for study designs with clearly defined exposure periods, at the very least in trimesters, and use advanced confounding adjustment methodology to increase the accuracy of the findings.

Selective Serotonin Reuptake Inhibitor Use During Pregnancy and Major Malformations: The Importance of Serotonin for Embryonic Development and the Effect of Serotonin Inhibition on the Occurrence of Malformations

Bioelectric signaling is transduced by neurotransmitter pathways in many cell types. One of the key mediators of bioelectric control mechanisms is serotonin, and its transporter SERT, which is targeted by a broad class of blocker drugs (selective serotonin reuptake inhibitors [SSRIs]). Studies showing an increased risk of multiple malformations associated with gestational use of SSRI have been accumulating but debate remains on whether SSRI as a class has the potential to generate these malformations. This review highlights the importance of serotonin for embryonic development; the effect of serotonin inhibition during early pregnancy on the occurrence of multiple diverse malformations that have been shown to occur in human pregnancies; that the risks outweigh the benefits of SSRI use during gestation in populations of mild to moderately depressed pregnant women, which encompass the majority of pregnant depressed women; and that the malformations seen in human pregnancies constitute a pattern of malformations consistent with the known mechanisms of action of SSRIs. We present at least three mechanisms by which SSRI can affect development. These studies highlight the relevance of basic bioelectric and neurotransmitter mechanism for biomedicine.

In utero oxcarbazepine and a withdrawal syndrome, anomalies, and hyponatremia

Oxcarbazepine is an antiepileptic agent that has been used during pregnancy, although its safety during pregnancy has not been sufficiently established. This article presents an infant born with renal and cardiac malformations who developed a withdrawal syndrome and hyponatremia following in utero exposure to oxcarbazepine. The infant was born at 35 weeks' gestation by urgent cesarean section to a mother in status epilepticus who had been treated with oxcarbazepine throughout her pregnancy. Evaluation for congenital anomalies identified mild aortic stenosis, a bicuspid aortic valve, patent foramen ovale, patent ductus arteriosus, and severe left hydronephrosis due to left ureteropelvic junction stenosis. On the third day of life the infant developed clinical signs of a withdrawal syndrome, which peaked on day 7 and resolved by day 12. Transient hyponatremia resolved by day 8 of life. Follow-up showed normal development at 15 months. The association of a withdrawal syndrome with oxcarbazepine exposure has not been previously reported. The hyponatremia is consistent with adult reports. The possible association of oxcarbazepine with renal and cardiac malformations requires further confirmation.

Agreement between self-report and prescription data in medical records for pregnant women

BACKGROUND Clinical teratology studies often rely on patient reports of medication use in pregnancy with or without other sources of information. Electronic medical records (EMRs), administrative databases, pharmacy dispensing records, drug registries, and patients' self-reports are all widely used sources of information to assess potential teratogenic effect of medications. The objective of this study was to assess comparability of self-reported and prescription medication data in EMRs for the most common therapeutic classes. METHODS The study population included 404 pregnant women prospectively recruited from five prenatal care clinics affiliated with the University of New Mexico. Self-reported information on prescription medications taken since the last menstrual period (LMP) was obtained by semistructured interviews in either English or Spanish. For validation purposes, EMRs were reviewed to abstract information on medications prescribed between the LMP and the date of the interview. Agreement was estimated by calculating a kappa (κ) coefficient, sensitivity, and specificity. RESULTS In this sample of socially-disadvantaged (i.e., 67.9% high school education or less, 48.5% no health insurance), predominantly Latina (80.4%) pregnant women, antibiotics and antidiabetic agents were the most prevalent therapeutic classes. The agreement between the two sources substantially varied by therapeutic class, with the highest level of agreement seen among antidiabetic and thyroid medications (κ ≥0.8) and the lowest among opioid analgesics (κ = 0.35). CONCLUSIONS Results indicate a high concordance between self-report and prescription data for therapeutic classes used chronically, while poor agreement was observed for medications used intermittently, on an 'as needed" basis, or in short courses.

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.

Use of selective serotonin-reuptake inhibitors during early pregnancy and risk of congenital malformations: updated analysis

BACKGROUND

Data on the safety of selective serotonin-reuptake inhibitors (SSRIs) in pregnancy are inconsistent. We examined associations between SSRI use during early pregnancy and risk of congenital malformations in infants.

METHODS

Set in Northern Denmark, our population-based prevalence study included 216,042 women who had a live birth after the 20th week of gestation. We compared the prevalence of malformation in infants born to women who redeemed at least one SSRI prescription during early pregnancy with the prevalence in infants born to women who redeemed no SSRI prescriptions during their pregnancies. Drug use data were extracted from prescription databases, while data on congenital malformations were obtained from the National Registry of Patients.

RESULTS

The 2,062 women with SSRI prescriptions during early pregnancy gave birth to 105 (5.1%) infants with malformations, while the 213,712 women with no SSRI prescriptions gave birth to 7,449 (3.5%) infants with malformations. SSRI use was associated with an increased risk of malformations overall (odds ratio [OR] = 1.3; 95% confidence interval (CI): 1.1-1.6) and cardiac malformations (OR = 1.7; 95% CI: 1.1-2.5). For specific SSRIs, we found an increased risk for septal defects associated with sertraline.

CONCLUSIONS

We found little overall association between use of SSRIs during pregnancy and congenital malformations, but our findings suggest an association between maternal SSRI use in early pregnancy and cardiac malformations which could be causal.

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.

Pregnancy outcomes in women with epilepsy: a systematic review and meta-analysis of published pregnancy registries and cohorts

PURPOSE

To conduct a systematic review and meta-analysis to quantify the incidence of congenital malformations (CMs) and other pregnancy outcomes as a function of in utero anti-epileptic drug (AED) exposure.

METHODS

We performed a systematic literature review to identify all published registries and cohort studies of births from pregnant women with epilepsy (WWE) that reported incidence of CMs. Overall incidences were calculated using a random effects model.

RESULTS

The review included 59 studies that met inclusion/exclusion criteria, involving 65,533 pregnancies in WWE and 1,817,024 in healthy women. The calculated incidence of births with CM in WWE [7.08%; 95% CIs 5.62, 8.54] was higher than healthy women [2.28%; CIs 1.46, 3.10]. Incidence was highest for AED polytherapy [16.78%; CIs 0.51, 33.05]. The AED with the highest CM incidence was valproate, which was 10.73% [CIs 8.16, 13.29] for valproate monotherapy.

CONCLUSIONS

Results of this systematic literature review suggest that the overall incidence of CMs in children born of WWE is approximately threefold that of healthy women. The risk is elevated for all AED monotherapy and further elevated for AED polytherapy compared to women without epilepsy. The risk was significantly higher for children exposed to valproate monotherapy and to polytherapy of 2 or more drugs when the polytherapy combination included phenobarital, phenytoin, or valproate. Further research is needed to delineate the specific risk for each individual AED and to determine underlying mechanisms including genetic risk factors.

Maternal use of fluconazole and risk of congenital malformations: a Danish population-based cohort study

OBJECTIVES

Fluconazole is widely used for the treatment of candidiasis. Although the drug is also prescribed to pregnant women, data on the safety of use of fluconazole during pregnancy are limited. We examined the association between the maternal use of fluconazole during pregnancy and the risk of congenital malformations.

PATIENTS AND METHODS

In this population-based cohort study in Northern Denmark, we included 1079 women who had a live birth or a stillbirth after the 20th week of gestation and who redeemed at least one prescription for fluconazole during the first trimester. The reference cohort comprised 170 453 pregnant women who redeemed no fluconazole prescription during pregnancy. The women were identified through the Danish Medical Birth Registry. Data on drug use, birth outcome and covariates were extracted from population-based healthcare databases. We used logistic regression to estimate the prevalence odds ratio (POR) for congenital malformations after fluconazole exposure, while adjusting for maternal smoking, parity, maternal age and concurrent prescriptions for antiepileptics or antidiabetics.

RESULTS

Among 1079 women who filled a fluconazole prescription during the first trimester, 797 (74%) received a total of 150 mg of fluconazole, 235 (22%) received 300 mg of fluconazole, 24 (2%) received 350 mg of fluconazole and 23 (2%) received 600 mg of fluconazole. These women gave birth to 44 (4.1%) children with congenital malformations. The 170 453 women without fluconazole prescriptions gave birth to 6152 (3.6%) children with congenital malformations. For congenital malformations overall, the adjusted POR associated with the first-trimester fluconazole use was 1.0 (95% confidence interval: 0.8-1.4).

CONCLUSIONS

We found no overall increased risk of congenital malformations after exposure to short-course treatment with fluconazole in early pregnancy.

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.

Therapeutic drug use in women with Crohn's disease and birth outcomes: a Danish nationwide cohort study

BACKGROUND

Crohn's disease (CD) is associated with increased risk of adverse birth outcomes. However, existing studies have not taken into account the impact of drug treatment. We examined the impact of drug treatment on birth outcomes--low birth weight (LBW), preterm birth, LBW at term, and congenital abnormalities (CAs)--among CD women.

METHODS

A nationwide Danish cohort study of 900 children born to CD women between 1996 and 2004, based on the National Registry of Patients, the Birth Registry, and the nationwide prescription database. Pregnancies were classified according to receipt of prescriptions for CD medication: no drugs (reference group), 5-aminosalicylic acid (5-ASA)/sulfasalazine, steroids, and azathioprine (AZA)/6-mercaptopurine (6-MP). We used logistic regression analyses to estimate the relative risk of birth outcomes with 95% confidence intervals. We used a proxy measure for disease activity.

RESULTS

Preterm births were more prevalent among steroid- and AZA/6-MP-exposed women (12.3% and 25%, respectively) compared with the reference group (6.5%). CAs were more prevalent among AZA/6-MP-exposed compared with reference group (15.4%vs 5.7%). Among steroid exposed, the risk of preterm birth was 1.4 (95% CI 0.6-3.3). Among AZA/6-MP exposed, the risk of preterm birth and CAs was 4.2 (95% CI 1.4-12.5) and 2.9 (95% CI 0.9-8.9), respectively.

CONCLUSIONS

The relative risk of adverse birth outcomes among CD women varied by type of drugs prescribed during pregnancy. The risk of preterm birth and CAs was greater when AZA/6-MP was prescribed, even after adjusting for confounders. However, further information is needed to determine whether the associations are causal.

Use of phenytoin, phenobarbital, or diazepam during pregnancy and risk of congenital abnormalities: a case-time-control study

PURPOSE

Case-control studies are often used to examine putative teratogenic drug effects during organogenesis but these studies are subject to confounding by indication, recall, and participation bias. The case-time-control approach is less susceptible to these sources of bias. We studied congenital abnormalities following exposure to phenytoin, phenobarbital, and diazepam in early pregnancy, i.e., second and third month, compared to mid-pregnancy, i.e., fifth and sixth month of pregnancy.

METHODS

We analyzed data from the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1996) in a case-time-control study.

RESULTS

The study included 22 843 children with congenital abnormalities (cases) and 38 151 children with no abnormalities (controls). Overall, odds ratio (OR) for congenital abnormalities after exposure to one of the three drugs in early pregnancy was 1.2 (95% confidence interval (CI): 1.0-1.4). Among children exposed to phenytoin OR for congenital abnormalities was 3.7 (95%CI: 0.3-49.6), for children exposed to phenobarbital the OR was 1.1 (95%CI 0.7-1.7), and for diazepam, OR for congenital abnormalities was 1.2 (95%CI: 1.0-1.4).

CONCLUSIONS

The associations we found between the drugs examined and congenital abnormalities were either only borderline significant or not statistically significant. The case-time-control study provides an interesting way of using existing case-control data to study rare side effect of drugs taken during pregnancy.

Treatment with oxcarbazepine during pregnancy

BACKGROUND

Managing epilepsy during pregnancy is a critical challenge as maternal seizures may have deleterious effects on the fetus. While many patients with epilepsy have been managed successfully with antiepileptic drugs (AEDs), the potential teratogenicity of AEDs is a major concern. First-generation AEDs such as valproate have been associated with at least a 2-fold risk of fetal malformations compared with the general population. However, recent studies suggest that the newer AEDs given as monotherapy may have a lower teratogenic risk. The current case report adds to the growing experience of oxcarbazepine therapy in pregnant women with epilepsy.

REVIEW SUMMARY

This case report presents a 23-year-old female with a history of complex partial seizures (CPS) and mild depression. In high school, she had 2 initial tonic-clonic seizures and was placed on phenytoin monotherapy. She was subsequently placed on combination therapy (phenytoin + gabapentin) and was maintained on it for several years. Preceding a planned pregnancy, the patient was switched to oxcarbazepine and tapered off both phenytoin and gabapentin. The patient was maintained on oxcarbazepine monotherapy with a seizure-free pregnancy and delivered a normal, healthy baby girl. The patient breast-fed the infant for 6 months, supplemented with infant formula without any adverse effects. Subsequently, the patient has had a healthy second child while receiving oxcarbazepine during her pregnancy.

CONCLUSION

Although there are very limited data in the literature, this case illustrates that a patient with a history of CPS can be treated with oxcarbazepine with no adverse effects during and after pregnancy.

Maternal Use of Selective Serotonin Reuptake Inhibitors and Risk of Congenital Malformations

BACKGROUND

Human data on the teratogenicity of selective serotonin reuptake inhibitors (SSRIs) are limited. We examined the association between SSRI use during early pregnancy and the risk of congenital malformations in the offspring.

METHODS

In a population-based cohort study from Denmark, we identified 1051 women who filled prescriptions for SSRIs from 30 days before conception to the end of the first trimester; of those, 453 filled the prescription during the second or third pregnancy month. We included 150,780 women with no SSRI prescriptions as a reference cohort. Drug use data were extracted from prescription databases. Data on congenital malformations and potential confounders were extracted from hospital discharge registries and the National Birth Registry.

RESULTS

The 150,780 women with no SSRI prescriptions gave birth to 5112 (3.4%) children with congenital malformations. The 1051 women with SSRI prescriptions any time during early pregnancy gave birth to 51 (4.9%) children with congenital malformations. The corresponding adjusted relative risk (aRRs) was 1.34 (95% confidence interval = 1.00-1.79). The 453 women with prescriptions during the second or third month of pregnancy gave birth to 31 (6.8%) children with congenital malformations. The corresponding aRR was 1.84 (1.25-2.71).

CONCLUSIONS

We found an increased risk of congenital malformations after exposure to SSRIs in early pregnancy. It is unclear whether the effects were causal or due to factors related to the underlying disease. There was no evidence that the association was specific to particular malformations.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVES

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

DESIGN

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

METHODS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

Risk of specific congenital abnormalities in offspring of women with diabetes

AIMS

To assess the extent to which the increased risk of congenital abnormalities seen in women with pre-gestational insulin-treated diabetes mellitus is unspecific or related to the embryology of specific organs.

METHODS

Cases with congenital abnormalities were identified in the population-based Hungarian Congenital Abnormality Registry from 1980 to 1996 with two newborn children without congenital abnormality selected from the National Birth Registry as controls. We adjusted for parity, maternal age, and use of antipsychotic drugs.

RESULTS

Among cases we found 63/22,843 babies with maternal diabetes compared with 50/38,151 in the control group [adjusted prevalence odds ratio (POR) 2.1; 95% CI 1.5-3.1]. The association was strongest for the following congenital abnormalities: renal agenesis (POR: 14.8; 95% CI, 3.5-62.1), obstructive congenital abnormalities of the urinary tract (POR: 4.3; 95% CI, 1.3-13.9), cardiovascular congenital abnormalities (POR: 3.4; 95% CI, 2.0-5.7), and multiple congenital abnormalities (POR: 5.0; 95% CI, 2.4-10.2).

CONCLUSIONS

These data indicate that pre-gestational maternal diabetes is associated with strong teratogenic effects on the kidney, urinary tract, and heart, and strongly associated with multiple congenital abnormalities. We found no material association between diabetes and spinal congenital abnormalities and limb deficiencies.

Safety of the newer antiepileptic drug oxcarbazepine during pregnancy

OBJECTIVE

Seizure control in pregnant women with epilepsy is vital, as maternal seizures may have deleterious consequences. The treatment of pregnant women with epilepsy is, however, complicated by the teratogenicity of older antiepileptic drugs (AEDs). In this review, the safety of the newer AED oxcarbazepine during pregnancy is assessed based on published pregnancy outcome data. Other relevant safety issues, such as oxcarbazepine pharmacokinetics during pregnancy and the compatibility of oxcarbazepine treatment with breastfeeding, are also discussed.

METHODS

Literature searches of the following databases were performed: MEDLINE, EMBASE, eNova, NOWIMA (an internal Novartis Germany database), Derwent Drug File, SciSearch and BIOSIS. Identified publications were examined for original data reporting rates of foetal malformation following maternal exposure to oxcarbazepine as monotherapy or adjunctive therapy.

RESULTS

Relevant publications reporting data from the worldwide Novartis safety database and pregnancy registries or study centres in six countries were identified. A total of 248 pregnancies involving maternal exposure to oxcarbazepine monotherapy and 61 involving adjunctive therapy were reported. There were six malformations among the monotherapy group, equating to a malformation rate of 2.4% (6/248). The malformation rate reported in the general population is 2-4%. There were four malformations associated with oxcarbazepine adjunctive therapy, equating to a malformation rate of 6.6% (4/61).

CONCLUSIONS

This literature review suggests that, compared with newborns in the general population, the newborns of women receiving oxcarbazepine monotherapy during pregnancy do not appear to show an increased risk for malformations. However, the number of pregnancies involving maternal exposure to oxcarbazepine identified by this review is not sufficient to draw definitive conclusions. Additional information from large-scale pregnancy registries is required to confirm the safety profile of oxcarbazepine as monotherapy or adjunctive therapy during pregnancy.

Pregnancy in women who have epilepsy

Ideal, comprehensive care of women who have epilepsy during the reproductive years must include effective preconceptional counseling and preparation. The importance of planned pregnancies with effective birth control should be emphasized, with consideration of the effects of the enzyme-inducing AEDs on lowering efficacy of hormonal contraceptive medications and the need for back-up barrier methods. Before pregnancy occurs, the patient's diagnosis and treatment regimen should be reassessed. Once the diagnosis of epilepsy is confirmed, it is important to verify if the individual patient continues to need medications and if she is taking the most appropriate AED to balance control of her seizures with teratogenic risks. For most women who have epilepsy, withdrawal of all AEDs before pregnancy is not a realistic option. A decision to undergo a trial while not taking AEDs before a planned pregnancy should be based on the same principles used for AED withdrawal in any person who has epilepsy. The taper should be completed at least 6 months before planned conception to provide some reassurance that seizures are not going to recur. If a woman who has epilepsy is in the more prevalent category of needing AEDs for seizure control, then monotherapy at the lowest effective dosage should be used. If large daily doses are needed, then frequent smaller doses or extended-release formulations may be helpful to avoid high peak levels. Some of the newest information about differential risks between AEDs also should be considered. The woman's AED regimen should be optimized and folate supplementation should begin before pregnancy. Given that 50% of pregnancies are unplanned in the United States, folate supplementation should be encouraged in all women of childbearing age who are taking any AED for any indication. Dosing recommendations vary from 0.4 mg/d to 5 mg/d. It is not uncommon for a physician to consider changing AED regimens when the patient first reports that she is pregnant. In many cases, she already is in or past the critical period of organogenesis (Table 3). If a woman who has epilepsy presents after conception and is taking a single AED that is effective, her medication usually should not be changed. Exposing the fetus to a second agent during a crossover period of AEDs only increases the teratogenic risk, and seizures are more likely to occur with any abrupt medication changes. If a woman is on polytherapy, it may be possible to switch to monotherapy safely. Seizure control remains an important goal during pregnancy. In particular, convulsive seizures place the mother and fetus at risk. Nonconvulsive seizures also may be harmful, especially if they involve falling or other forms of trauma. Monitoring serum AED levels during pregnancy can be helpful in optimizing seizure control. Prenatal screening can detect major malformations in the first and second trimesters. Vitamin K1 is given 10 mg/d orally during the last month of pregnancy followed by 1 mg intramuscularly or intravenously to the new-born. Although women who have epilepsy and women who are taking AEDs for other indications do have increased risks for maternal and fetal complications, these risks can be reduced considerably with effective preconceptional planning and careful management during pregnancy and the postpartum period.

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.

Fetal alcohol syndrome: diagnosis, epidemiology, and developmental outcomes

In Australia the issue of fetal alcohol syndrome (FAS) has not been the subject of policy development or of extensive research. There is a lack of knowledge, both in the general community and by health professionals, of the nature of the risks associated with heavy alcohol consumption during pregnancy and the factors that increase this risk. This paper reviews the literature surrounding FAS with the aim of providing the reader an understanding of the diagnostic features and epidemiology of FAS and of the developmental sequelae associated with this syndrome.

Teratogenic potential of the newer antiepileptic drugs: what is known and how should this influence prescribing?

The treatment of women of childbearing age who have epilepsy raises many questions because of the interactions between epilepsy, antiepileptic therapy and different aspects of reproductive life. Menstrual cycle disorders and reduced fertility have been partially ascribed to antiepileptic drugs (AEDs). Furthermore, most AEDs induce the cytochrome P450 (CYP) enzymatic system, altering the metabolism of sex hormones and contributing to the failure of oral contraceptives. Pregnancy represents, in this context, the most critical period because of the well known teratogenic potential of all established AEDs. For most of these drugs no specific patterns of malformations have been identified, although during the past few decades basic knowledge has been acquired, particularly concerning the mechanisms of AED-induced teratogenesis and related risk factors. These issues form the basis of the current guidelines for the management of epilepsy in pregnant women. In the past decade, several new AEDs have been introduced into clinical practice. For a number of reasons, these drugs appear to be more favourable than the older ones as treatments for epilepsy in women of childbearing age. They possess a good pharmacokinetic profile that makes them more stable during pregnancy, and they have a low potential for interaction with other drugs. They are also less likely than the older AEDs to be metabolised to compounds that are teratogenic. Furthermore, most of them do not possess antifolate properties. With the exception of topiramate and vigabatrin, the newer AEDs do not appear to be teratogenic in animals when administered in subtoxic doses. However, animal teratology may not be a reliable predictor of human teratogenicity, and there is a significant lack of information regarding the teratogenic profile of these newer agents in humans. Because clinical experience with these agents is limited, it is advisable to avoid exposure of the embryo to these drugs when pregnancy is planned. The establishment of pregnancy registries could allow for the rapid collection of data related to the administration of new AEDs in pregnancy and the outcomes of such exposure.

Maternal antiepileptic drug use and effects on fetal development

Many pregnant women take antiepileptic medications, and concern has arisen about the risks this poses to the fetus. It has been debated whether the causative agent is the medication or the underlying maternal disorder. Review of the recent literature indicates that the effects seem to be from the medications themselves. The frequency of malformations is about two to three-fold above the background rate and is dose-related for some of the medications. There seem to be effects on birth weight, length, and head circumference caused by at least some of the medications. The risks are greater when more than one medication is used. Cognitive effects from the medications have been shown, although these effects are of lower magnitude than previously reported. More investigation needs to be done to determine the exact risks of each individual medication, especially the newer ones. Studies on underlying mechanisms indicate potential genetic susceptibility and altered developmental gene expression patterns.