Prescribing patterns for higher dose folic acid in pregnant women with epilepsy treated with antiseizure medication.

OBJECTIVE: This study was undertaken to characterize the use of higher doses of folic acid (≥1 mg daily) in relation to pregnancy in Denmark, Norway, and Sweden in women with epilepsy treated with antiseizure medication (ASM). METHODS: In this observational study, we used data from national medical birth, patient, and prescription registers in Denmark, Norway, and Sweden to retrospectively identify pregnancies in women with epilepsy treated with ASM from 2006 to 2017. The proportion of higher dose folic acid supplementation in pregnancies among women receiving ASM for epilepsy was calculated according to country of origin, time period, and type of ASM. Logistic regression with restricted cubic splines was used to model country-specific time trends. RESULTS: Among a total of 2 748 882 pregnancies, we identified 8695 (.3%) pregnancies after restricting the population to women with ASM-treated epilepsy. A prescription for higher dose folic acid was filled in 4719 (54.3%) of these pregnancies. The proportion supplemented with higher dose folic acid was highest in Sweden (74.3%) and lower in Norway (41.4%) and Denmark (34.3%). Furthermore, we observed a decreasing trend of higher dose folic acid use in Denmark and Norway from year 2012 to 2017. Among those who used higher dose folic acid, 42% did not start preconception supplementation with higher dose folic acid. SIGNIFICANCE: Supplementation with higher dose folic acid occurred in approximately half of pregnancies in women with ASM-treated epilepsy, with many not starting supplementation until after becoming pregnant. Considerable variability was observed in the use of higher dose folic acid across the countries, despite similar population characteristics and health care systems. Future guidelines should be simplified with clear recommendations developed in a collaborative manner by relevant specialists including neurologists, obstetricians, pediatricians, and public health specialists to enhance real-world applicability.

High-dose folic acid and cancer risk; unjustified concerns by von Wrede and colleagues regarding our paper.

Women using antiseizure medication in pregnancy are often advised to use high doses of folic acid supplements (1mg to 5 mg) to reduce the risk of teratogenicity. Recently, we published a report showing an association between maternal prescription fill of high dose folic acid in relation to pregnancy and childhood cancer in the offspring. The report has sparked a debate about which dose of folic acid that should be recommended in pregnancy in women in need of antiseizure medication. In this Commentary, we explain our findings and the method used in our report, and answer recent questions that have emerged.

Prenatal Exposure to Antiseizure Medications and Risk of Epilepsy in Children of Mothers With Epilepsy.

Importance: Use of valproate and certain other antiseizure medications (ASMs) in pregnancy is associated with abnormal fetal brain development with potential long-term implications for the child. Objective: To examine whether use of valproate and other ASMs in pregnancy among mothers with epilepsy is associated with epilepsy risk in their children. Design, Setting, and Participants: This prospective, population-based register cohort study included singletons born to mothers with epilepsy in Denmark, Finland, Iceland, Norway, and Sweden from January 1, 1996, to December 31, 2017. Data analysis was performed from October 2022 to December 2023. Exposure: Redeemed prescription for an ASM from 30 days before pregnancy until birth. Main Outcomes and Measures: The main outcome was epilepsy in children, assessed using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnoses from hospital care. Adjusted hazard ratios (AHRs) and 95% CIs were estimated using Cox proportional hazards regression. Secondary analyses included dose-response analyses, analyses using children of mothers who discontinued ASM prior to pregnancy as the reference, and sibling analyses. Results: This cohort study included 38 663 children of mothers with epilepsy (19 854 [51.4%] boys). Children were followed up from birth; the mean length of follow-up was 7.2 years (range 0-22 years). Compared with 22 207 children of mothers not using an ASM in pregnancy, increased risks of epilepsy in children of mothers who used valproate in pregnancy (monotherapy: AHR, 2.18; 95% CI, 1.70-2.79; polytherapy: AHR, 2.10; 95% CI, 1.49-2.96) were observed. However, there was no dose-dependent association, and there was a similar risk of epilepsy in siblings who were exposed and unexposed to valproate (AHR, 0.95; 95% CI, 0.50-1.82). Prenatal exposure to topiramate monotherapy was associated with increased risk of epilepsy (AHR, 2.32; 95% CI, 1.30-4.16), and the risk was greater for higher doses, but the risk attenuated in comparisons with children of mothers who discontinued topiramate before pregnancy (AHR, 1.19; 95% CI, 0.26-5.44). Prenatal exposure to clonazepam monotherapy was also associated with increased epilepsy risk (AHR, 1.90; 95% CI, 1.16-3.12), but limited follow-up and low numbers precluded further analyses. No associations were observed for prenatal exposure to lamotrigine (AHR, 1.18; 95% CI, 0.95-1.47), levetiracetam (AHR, 1.28; 95% CI, 0.77-2.14), carbamazepine (AHR, 1.13; 95% CI, 0.85-1.50), or oxcarbazepine (AHR, 0.68; 95% CI, 0.44-1.05). Conclusions and Relevance: In this cohort study of children born to mothers with epilepsy, the associations found between prenatal exposure to certain ASMs and the child's risk of epilepsy did not persist in sensitivity analyses, suggesting that maternal ASM use in pregnancy may not increase epilepsy risk in children beyond that associated with the maternal epilepsy itself. These findings are reassuring for women in need of treatment with ASM in pregnancy.

Cancer Risk in Children of Mothers With Epilepsy and High-Dose Folic Acid Use During Pregnancy.

Importance: Women with epilepsy are recommended high doses of folic acid before and during pregnancy owing to risk of congenital anomalies associated with antiseizure medications. Whether prenatal exposure to high-dose folic acid is associated with increases in the risk of childhood cancer is unknown. Objective: To assess whether high-dose folic acid supplementation in mothers with epilepsy is associated with childhood cancer. Design, Setting, and Participants: Observational cohort study conducted with nationwide registers in Denmark, Norway, and Sweden from 1997 to 2017. Analyses were performed during January 10, 2022, to January 31, 2022. Mother-child pairs were identified in medical birth registers and linked with information from patient, prescription, and cancer registers, as well as with sociodemographic information from statistical agencies, and were categorized by maternal diagnosis of epilepsy. The study population consisted of 3 379 171 children after exclusion of 126 711 children because of stillbirth or missing or erroneous values on important covariates. Exposures: Maternal prescription fills for high-dose folic acid tablets (≥1 mg daily) between 90 days before pregnancy start and birth. Main Outcomes and Measures: First onset of childhood cancer at younger than 20 years. Cox proportional hazards models were used to calculate adjusted hazard ratios with corresponding 95% CIs, adjusted for potential confounders. Cumulative incidence at aged 20 years was used as a measure of absolute risk. Results: The median age at the end of follow-up in the study population of 3 379 171 children was 7.3 years (IQR, 3.5-10.9 years). Among the 27 784 children (51.4% male) born to mothers with epilepsy, 5934 (21.4%) were exposed to high-dose folic acid (mean dose, 4.3 mg), with 18 exposed cancer cases compared with 29 unexposed, producing an adjusted hazard ratio of 2.7 (95% CI, 1.2-6.3), absolute risk if exposed of 1.4% (95% CI, 0.5%-3.6%), and absolute risk if unexposed of 0.6% (95% CI, 0.3%-1.1%). In children of mothers without epilepsy, 46 646 (1.4%) were exposed to high-dose folic acid (mean dose, 2.9 mg), with 69 exposed and 4927 unexposed cancer cases and an adjusted hazard ratio of 1.1 (95% CI, 0.9-1.4; absolute risk, 0.4% [95% CI, 0.3%-0.5%]). There was no association between children born to mothers with epilepsy who were prenatally exposed to antiseizure medications, but not high-dose folic acid, and an increased risk of cancer (absolute risk, 0.6%; 95% CI, 0.2%-1.3%). Conclusions and Relevance: Prenatal exposure to high-dose folic acid was associated with increased risk of cancer in children of mothers with epilepsy.