Should valproate be taken during pregnancy?

Endocrine disrupting effects on morphological synaptic plasticity

Neural regulation of the homeostasis depends on healthy synaptic function. Adaptation of synaptic functions to physiological needs manifests in various forms of synaptic plasticity (SP), regulated by the normal hormonal regulatory circuits. During the past several decades, the hormonal regulation of animal and human organisms have become targets of thousands of chemicals that have the potential to act as agonists or antagonists of the endogenous hormones. As the action mechanism of these endocrine disrupting chemicals (EDCs) came into the focus of research, a growing number of studies suggest that one of the regulatory avenues of hormones, the morphological form of SP, may well be a neural mechanism affected by EDCs. The present review discusses known and potential effects of some of the best known EDCs on morphological synaptic plasticity (MSP). We highlight molecular mechanisms altered by EDCs and indicate the growing need for more research in this area of neuroendocrinology.

Valproic Acid in Pregnancy Revisited: Neurobehavioral, Biochemical and Molecular Changes Affecting the Embryo and Fetus in Humans and in Animals: A Narrative Review

Valproic acid (VPA) is a very effective anticonvulsant and mood stabilizer with relatively few side effects. Being an epigenetic modulator, it undergoes clinical trials for the treatment of advanced prostatic and breast cancer. However, in pregnancy, it seems to be the most teratogenic antiepileptic drug. Among the proven effects are congenital malformations in about 10%. The more common congenital malformations are neural tube defects, cardiac anomalies, urogenital malformations including hypospadias, skeletal malformations and orofacial clefts. These effects are dose related; daily doses below 600 mg have a limited teratogenic potential. VPA, when added to other anti-seizure medications, increases the malformations rate. It induces malformations even when taken for indications other than epilepsy, adding to the data that epilepsy is not responsible for the teratogenic effects. VPA increases the rate of neurodevelopmental problems causing reduced cognitive abilities and language impairment. It also increases the prevalence of specific neurodevelopmental syndromes like autism (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). High doses of folic acid administered prior to and during pregnancy might alleviate some of the teratogenic effect of VPA and other AEDs. Several teratogenic mechanisms are proposed for VPA, but the most important mechanisms seem to be its effects on the metabolism of folate, SAMe and histones, thus affecting DNA methylation. VPA crosses the human placenta and was found at higher concentrations in fetal blood. Its concentrations in milk are low, therefore nursing is permitted. Animal studies generally recapitulate human data.

Outcomes of pregnancies in women taking antiepileptic drugs for non-epilepsy indications

PURPOSE

Antiepileptic drugs (AEDs), particularly valproate (VPA), are known to be teratogens when taken by women with epilepsy (WWE), but the risk in women who take these drugs for indications other than epilepsy have been little studied. This study aims to investigate the incidence of birth defects in children born to mothers taking AEDs for non-epilepsy indications.

METHODS

The Australian Pregnancy Register (APR), established in 1998, is a prospective observational study operating with ethical approval and informed written consent for participation. Of the 2066 pregnancies enrolled in the Register, 98% are WWE and the remainder received AEDs for other indications. Data from this Register was analysed to study the rates of congenital malformations (CM) in infants exposed to AEDs in utero in WWE compared to those women taking AEDs for other indications.

RESULTS

The malformation rates in pregnancies of WWE taking AEDs (5%), is higher than the rates of infants born to untreated WWE (2%). There were 32 pregnancies enrolled from 29 mothers taking AEDs for indications other than epilepsy (2 women/2 pregnancies were lost to follow up). Out of 30 pregnancies, 9 of which were exposed to VPA, 1 resulted in a child with a malformation (3%) (cleft palate) on 1700 mg/day of valproate.

CONCLUSIONS

This is the first attempt to assess the use of AEDs in a prospective study of women who are pregnant but do not have active epilepsy. Although underpowered, this study suggests that women taking AEDs for non-epilepsy indications have a similar risk of having a child with a CM as compared with women taking AEDs for epilepsy. Larger numbers are required to investigate the risk of AED-associated malformations in this important group.

Fetal Valproate Syndrome

BACKGROUND

There have been several reports of congenital malformations in the offspring of mothers who took valproic acid (VPA) during pregnancy as a treatment for epilepsy.

METHODS

Herein, we describe four cases with typically similar facial features of fetal valproate syndrome accompanied to minor skeletal abnormalities.

RESULTS

The first case was a 16-month-old girl, presenting with facial dysmorphism, and finger abnormalities. Her mother took VPA (1500 mg/d) up to the 10^th gestational week and at a dosage of 1000 mg/d through the pregnancy. The second patient was 5-year-old boy with speech disability, bilateral cryptorchidism, facial dysmorphism, and finger abnormalities whose mother took VPA (1000 mg/d) through pregnancy. The third 19-month-old patient was the brother of the second patient who had facial dysmorphism, bilateral cryptorchidism, and finger abnormalities. His mother also took VPA (1000 mg/d) through pregnancy. The fourth 3-year and 6 month-old boy with minor facial dysmorphism and sternum deformity was exposed to VPA (500 mg/d) in utero.

CONCLUSION

In conclusion, there is a recognizable spectrum of abnormalities in some infants exposed to VPA without dose-depence and the common facial dysmorphic features and minor skeletal abnormalities that may occur within the both low and high dose VPA use.

Teratogenesis in repeated pregnancies in antiepileptic drug-treated women

PURPOSE

Considerable information is now available concerning the risk of teratogenesis in the individual pregnancy exposed to antiepileptic drugs (AEDs). However, there is comparatively little information available concerning the risk in the subsequent pregnancies of women who continue to take the AED associated with a fetal malformation in a previous pregnancy. This article addresses this matter.

METHODS

Analysis of data concerning fetal abnormalities in 1,243 women who had 2,637 pregnancies between mid-1999 and 2010 recorded in the Australian Register of Antiepileptic Drugs in Pregnancy. Of the 2,637 pregnancies, 1,114 had been completed before initial enrolment in the Register.

KEY FINDINGS

Women taking any AED who had given birth to a malformed baby in their first enrolled pregnancy and who continue taking the same drug were at increased risk of having a malformed offspring in their next pregnancy (35.7% vs. 3.1%; odds ratio [OR] 17.6; 95% confidence interval [95% CI] 4.5-68.7). Among these women, those taking valproate (VPA) were more likely to have malformed fetuses in their next pregnancies than those who had taken VPA without fetal abnormalities (57.2% vs. 7.0%, OR 17.8; 95% CI 2.7, 119.1). There were similar although not statistically significant trends in those who had taken AEDs other than VPA. Similar, although again not statistically significant, trends were found, when considering the pairings of the most recent preenrollment pregnancy and the following one. If a woman had two or more pregnancies that resulted in AED-associated fetal malformation, the types of malformation were often different.

SIGNIFICANCE

Women whose last pregnancy resulted in a fetal malformation have a substantially increased risk of having further malformed fetuses if they become pregnant again while taking the same AED, particularly VPA. This suggests that maternal factors, perhaps genomic, predispose to at least VPA-associated malformations. This knowledge, together with information about the outcome of any previous pregnancy, should help in advising women with AED-treated epilepsy who plan further pregnancies.

The Australian antiepileptic drug in pregnancy register: Aspects of data collection and analysis

Internal comparisons using the data of the Australian Register of Antiepileptic Drugs in Pregnancy as of November 2005, and comparisons with Australian population data, were carried out. It was found that (i) except for under-representation of mothers of Asian origin, the demography of the register population was reasonably representative of the Australian situation; (ii) except for more pregnancies terminated for foetal malformation, malformation rates were similar in retrospectively and non-retrospectively enrolled pregnancies; (iii) some 21% of foetal malformations would have been excluded by not including malformations first recognised after the neonatal period; and (iv) in practice, the comparator against which malformation rates were expressed made little difference to the rates found. It is desirable to have available such analyses of pregnancy register data before comparing the findings of different registers.

Pharmacotherapy of epilepsy: new armamentarium, new issues

Since 1990 there have been over ten antiepileptic drugs (AEDs) approved for the therapy of epilepsy. These agents have a new spectrum of efficacy and novel adverse effects, some totally unexpected. They also represent an enormous escalation of costs. Few have been subjected to head-to-head comparisons in monotherapy against established AEDs. The aim of therapy is to eliminate rather than to reduce seizure manifestations. Many traditional agents have been phased out due to poor tolerability. New epilepsy syndromes and genetic contributions to epilepsy have been refined. Special considerations apply to various classes of sufferers such as the elderly, women of childbearing age, and sufferers with concomitant disorders, treated with medications capable of drug interactions. There is a recognition of the value of slow introduction, a preference for monotherapy, recognition of the effects of AEDs on hormones and reproductive function and effects on the fetus exposed to AEDs in utero, comprising physical malformations and effects on cognitive development. A balance between efficacy and safety is pivotal, as every preference about the initial pharmacotherapy of epilepsy and subsequent polytherapy has its protagonists. With improvement in diagnostic techniques and new therapeutic modalities it is likely that in the future, pharmacogenomics and an understanding of pharmacoresistance may influence drug selection for individual patients with epilepsy.

Changing Australian prescribing patterns for antiepileptic drugs in pregnancy and their possible consequences

We report progress in the accumulation of data by the Australian Pregnancy Register over 64 months, confirming the rise in enrollment and the predominantly epileptic indication for taking antiepileptic drugs. Eighty percent of the enrollment was prospective. The focus of the current report is the observation that as a possible result of education and dissemination of information about the risks of exposure to high-dose valproate, there has been a decline in the drug's doses prescribed in Australia, as well as a decline in the proportion of patients prescribed this drug in pregnancy. The risk of teratogenicity associated with valproate in doses in excess of 1100 mg/day was confirmed, and the incidence of lamotrigine-related malformations was comparable to that associated with exposure to phenytoin and carbamazepine. Reporting of data for this paper took into account the 12 months follow-up period for each pregnancy outcome, thus in effect making the evaluation period 21 months for each pregnancy and its outcome.

Maternal valproate dosage and foetal malformations

OBJECTIVE- To study the possible dose dependence of the foetal malformation rate after exposure to sodium valproate in pregnancy METHODS- Analysis of records of all foetuses in the Australian Registry of Antiepileptic Drugs in Pregnancy exposed to valproate, to carbamazepine, lamotrigine or phenytoin in the absence of valproate, and to no antiepileptic drugs. RESULTS- The foetal malformation rate was higher (P<0.05) in the 110 foetuses exposed to valproate alone (17.1%), and in the 165 exposed to valproate, whether alone or together with the other antiepileptic drugs (15.2%), than in the 297 exposed to the other drugs without valproate (2.4%). It was also higher (P<0.10) than in the 40 not exposed to antiepileptic drugs (2.5%). Unlike the situation for the other drugs, the malformation rate in those exposed to valproate increased with increasing maternal drug dosage (P<0.05). The rate was not altered by simultaneous exposure to the other drugs. Valproate doses exceeding 1400 mg per day seemed to be associated with a more steeply increasing malformation rate than at lower doses and with a different pattern of foetal malformations. CONCLUSIONS- Foetal exposure to valproate during pregnancy is associated with particularly high, and dose-dependent risks of malformation compared with other antiepileptic drugs, and may possibly involve different teratogenetic mechanisms.