Paternal exposure to antiepileptic drugs and offspring outcomes: a nationwide population-based cohort study in Sweden

Paternal exposure to antiseizure medications and offspring outcomes: a systematic review

BACKGROUND

Concerns have recently been raised about risks to the fetus resulting from paternal exposure to antiseizure medications (ASMs). To address these concerns, we conducted a systematic review of the literature to assess neurodevelopmental and anatomical outcomes in offspring born to fathers taking ASMs at the time of conception.

METHODS

Electronic searches of MEDLINE, PsycINFO, and Embase were conducted to identify human studies published in English that reported on outcomes, comprising neurodevelopmental disorders, major congenital malformations, small-for-gestational age or low birth weight, in offspring of fathers taking ASMs at conception. Quality analysis of included studies was undertaken using the Newcastle-Ottawa Scale. A narrative synthesis was used to report study findings.

RESULTS

Of 923 studies identified by the search and screened by title and abstract, 26 underwent full-text review and 10 met eligibility criteria. There was limited evidence available, but there appeared to be no clear evidence for an adverse impact of paternal ASM use on offspring outcomes. Few isolated adverse findings were not replicated by other investigations. Several methodological limitations prevented meta-analysis, including failure by most studies to report outcomes separately for each individual ASM, heterogeneity in measurement and outcome reporting, and small numbers of monotherapy exposures.

CONCLUSIONS

Although there were limited data available, this systematic review provides reassuring evidence that paternal exposure to ASMs at conception is unlikely to pose any major risk of adverse outcomes for the offspring. Further research is needed to examine the relationship between preconception ASM use in males and offspring outcomes at birth and postnatally.

New valproate regulations, informed choice and seizure risk

Valproate is the most effective medication for generalised epilepsies, and several specific epilepsy syndromes. For some people, it will be the only medication to establish seizure remission, and withdrawing it carries risks of seizure recurrence and Sudden Unexpected Death in Epilepsy (SUDEP). It is also of proven efficacy for bipolar disorder and migraine prevention. Guidelines based on observational and epidemiological studies stress that maternal valproate related teratogenicity and neurodevelopmental effects are significantly higher than for other antiseizure medications (ASMs). It should, therefore, only be used if other medications are ineffective and after balancing the teratogenicity risk. Regulatory restrictions have changed prescribing practices and reduced valproate use. The number of other medications that must be trialled in the different conditions for which valproate has effectiveness and the consequences of the lack of efficacy of those drugs leading to significant harm including death remains unexplored. Risk minimisation measures (RMMs) for valproate, chiefly Pregnancy Prevention practices (PPP), consider foetal risk and not risk to people living with epilepsy. In the United Kingdom (UK), limitations relating to valproate use in all people < 55 years commenced in January 2024. While the evidence in child-bearing women is not disputed, the data in males are based on animal models, case reports, and one commissioned, unpublished, non-peer reviewed report unavailable to the UK public, stakeholder charities or professionals. Evidence suggests that 30-40% of people switching from valproate have breakthrough seizures. Thus, an estimated 21,000-28000 people in the UK will imminently be exposed to the potential hazards of breakthrough seizures, including death. There is little government investment in monitoring the effects of these changes to valproate prescribing on patient health and quality of life. This review summarises the history of valproate regulation, evidence underpinning it and argues how the latest regulations in the UK do not align with the country's medical regulatory bodies ethical principles nor with the Montgomery principles of informed patient choice and autonomy. It dissects how such regulations infringe Common Law principles, nor give due regard for patient outcomes beyond reproduction. The paper looks to provide recommendations to redress these concerns while appreciating the core need for such governance to emerge in the first place.

A Real-World Safety Profile in Neurological, Skin, and Sexual Disorders of Anti-Seizure Medications Using the Pharmacovigilance Database of the Korea Adverse Event Reporting System (KAERS)

(1) Background: The utilization of high-quality evidence regarding the safety of anti-seizure medications (ASMs) is constrained by the absence of standardized reporting. This study aims to examine the safety profile of ASMs using real-world data. (2) Methods: The data were collected from the Korea Adverse Event Reporting System Database (KAERS-DB) between 2012 and 2021. In total, 46,963 adverse drug reaction (ADR)-drug pairs were analyzed. (3) Results: At the system organ class level, the most frequently reported classes for sodium channel blockers (SCBs) were skin (37.9%), neurological (16.7%), and psychiatric disorders (9.7%). For non-SCBs, these were neurological (31.2%), gastrointestinal (22.0%), and psychiatric disorders (18.2%). The most common ADRs induced by SCBs were rash (17.8%), pruritus (8.2%), and dizziness (6.7%). Non-SCBs were associated with dizziness (23.7%), somnolence (13.0%), and nausea (6.3%). Rash, pruritus, and urticaria occurred, on average, two days later with SCBs compared to non-SCBs. Sexual/reproductive disorders were reported at a frequency of 0.23%. SCBs were reported as the cause more frequently than non-SCBs (59.8% vs. 40.2%, Fisher's exact test, p < 0.0001). (4) Conclusions: Based on real-world data, the safety profiles of ASMs were identified. The ADRs induced by SCBs exhibited different patterns when compared to those induced by non-SCBs.

Valproate Use During Spermatogenesis and Risk to Offspring

Importance

Concerns exist about teratogenic and long-term neurodevelopmental outcomes of paternal use of valproate during spermatogenesis.

Objective

To evaluate the association between paternal use of valproate during spermatogenesis and offspring risk of congenital malformations and neurodevelopmental disorders.

Design, Setting, and Participants

This nationwide cohort study included 1 235 353 singletons born in Denmark between January 1, 1997, and December 31, 2017, identified in the Medical Birth Register; 1336 children had fathers who had filled prescriptions for valproate during spermatogenesis. Congenital malformations were identified in the first year of life and neurodevelopmental disorders were identified from 1 year of age until December 31, 2018. Statistical analysis was performed March 2024.

Exposures

Paternal valproate exposure was defined as fathers who filled 1 or more prescriptions for valproate immediately before or during the time of spermatogenesis (ie, 3 months prior to conception).

Main Outcomes and Measures

Children with major congenital malformations in the first year of life and with neurodevelopmental disorders before death or end of follow-up were identified in Danish health registers. Log-binomial regression was used to estimate adjusted relative risks (ARRs) of congenital malformations, and Cox proportional hazards regression was used to estimate adjusted hazards ratios (AHRs) of neurodevelopmental disorders, adjusted for relevant confounders.

Results

Among 1 235 353 live births (634 415 boys [51.4%] and 600 938 girls [48.6%]), 1336 children (0.1%) had fathers who filled prescriptions for valproate during spermatogenesis. The median follow-up was 10.1 years (IQR, 5.1-14.8 years) for valproate-exposed children and 10.3 years (IQR, 5.2-15.6 years) for valproate-unexposed children. A total of 43 903 children (3.6%) received a diagnosis of major congenital malformations in the first year of life, and 51 633 children (4.2%) received a diagnosis of neurodevelopmental disorders during follow-up. When comparing the risk among valproate-exposed children with that among unexposed children, the ARR of major congenital malformations was 0.89 (95% CI, 0.67-1.18), the AHR of neurodevelopmental disorders was 1.10 (95% CI, 0.88-1.37), and the AHR of autism spectrum disorder was 0.92 (95% CI, 0.65-1.30). In analyses addressing the robustness of the findings (ie, dose-response analyses, sibling analyses, analyses restricted to children of fathers with epilepsy, analyses that used children with paternal lamotrigine exposure as active comparator, and analyses that used children with paternal exposure to valproate only before spermatogenesis as a negative control exposure), there still was no increased risk of any of the included end points.

Conclusions and Relevance

In all analyses based on this large Danish cohort study, results suggest that exposure to valproate during spermatogenesis was not associated with offspring risk of congenital malformations or neurodevelopmental disorders, including autism spectrum disorder.

Paternal preconception exposure to non-steroid anti-inflammatory drugs or opioids and adverse birth outcomes: A nationwide registry-based cohort study

BACKGROUND AND AIM

Paternal use of analgesics during the time of conception and adverse birth outcomes are poorly studied. We investigated the association between paternal exposure to non-steroid anti-inflammatory drugs and opioids within 3 months before the date of conception and the risk of adverse birth outcomes (preterm birth, small for gestational age, low Apgar score, and major congenital malformations).

METHODS

We used nationwide data from the Danish health registers. We included information on all singleton live births, and their fathers and mothers from 1997 to 2018. We created two exposed cohorts, children with preconception paternal exposure to (1) non-steroid anti-inflammatory drugs and (2) opioids. The unexposed cohort was children without preconception paternal exposure to non-steroid anti-inflammatory drugs or opioids, and we performed a sub-analysis against paternal use of acetaminophen (paracetamol). We used logistic regression models to estimate the odds ratios of adverse birth outcomes including 95% confidence intervals.

RESULTS

We identified 1,260,934 children, 45,667 children with paternal exposure to non-steroid anti-inflammatory drugs, 10,086 children with paternal exposure to opioids, and 1,205,181 unexposed children. The adjusted odds ratio for preterm birth was 1.08 (95% confidence interval, 1.03-1.13) after paternal exposure to non-steroid anti-inflammatory drugs and 1.21 (95% confidence interval, 1.08-1.35) after paternal exposure to opioids. The adjusted odds ratio for small for gestational age was 1.09 (95% confidence interval, 1.03-1.17) after paternal exposure to non-steroid anti-inflammatory drugs, and 1.03 (95% confidence interval, 0.88-1.21) after paternal exposure to opioids. We found null-associations for a low Apgar score and major congenital malformations. Estimates were attenuated when compared against paternal paracetamol exposure.

CONCLUSIONS

Overall, we found null-associations across the comparisons made. Weak associations were found for paternal exposure to non-steroid anti-inflammatory drugs or opioids and preterm birth and small for gestational age, but not with low Apgar score or major congenital malformation. All associations were attenuated when compared against an active comparator of paternal paracetamol exposure. The effect sizes were small and less likely to be of clinical relevance.

Beyond Genes: Germline Disruption in the Etiology of Autism Spectrum Disorders

Investigations into the etiology of autism spectrum disorders have been largely confined to two realms: variations in DNA sequence and somatic developmental exposures. Here we suggest a third route-disruption of the germline epigenome induced by exogenous toxicants during a parent's gamete development. Similar to cases of germline mutation, these molecular perturbations may produce dysregulated transcription of brain-related genes during fetal and early development, resulting in abnormal neurobehavioral phenotypes in offspring. Many types of exposures may have these impacts, and here we discuss examples of anesthetic gases, tobacco components, synthetic steroids, and valproic acid. Alterations in parental germline could help explain some unsolved phenomena of autism, including increased prevalence, missing heritability, skewed sex ratio, and heterogeneity of neurobiology and behavior.

Epilepsy in Pregnancy—Management Principles and Focus on Valproate

An estimated 60 million people worldwide suffer from epilepsy, half of whom are women. About one-third of women with epilepsy are of childbearing age. The childbirth rate in women with epilepsy is about 20–40% lower compared to that of the general population, which may be partly due to a lower number of these women being in relationships. Lower fertility in women with epilepsy may be linked to the disease itself, but it is mainly a result of the treatment provided. Valproate, as an antiepileptic drug inhibiting histone deacetylases, may affect the expression of genes associated with cell cycle control and cellular differentiation. Evidently, this drug is associated with the risk of malformations although other antiepileptic drugs (AEDs) may also trigger birth defects, however, to a lower degree. Valproate (and to a certain degree other AEDs) may induce autism spectrum disorders and attention deficit hyperactivity disorder. The main mechanism responsible for all negative effects of prenatal exposure to valproate seems inhibition of histone deacetylases. Animal studies show a reduction in the expression of genes involved in social behavior and an increase in hippocampal cytokines. Valproate-induced oxidative stress may also contribute to neural tube defects. Interestingly, paternal exposure to this AED in mice may trigger neurodevelopmental disorders as well although a population-based cohort study does not confirm this effect. To lower the risk of congenital malformations and neurodevelopmental disorders, a single AED at the optimal dose and supplementation with folic acid is recommended. VPA should be avoided in women of childbearing age and especially during pregnancy.

A systematic review of the biological, social, and environmental determinants of intellectual disability in children and adolescents

AIM

This systematic review aimed to identify the most important social, environmental, biological, and/or genetic risk factors for intellectual disability (ID).

METHODS

Eligible were published prospective or retrospective comparative studies investigating risk factors for ID in children 4-18 years. Exclusions were single group studies with no comparator without ID and a sample size <100. Electronic databases (Medline, Cochrane Library, EMBASE, PsycInfo, Campbell Collaboration, and CINAHL) were searched for eligible publications from 1980 to 2020. Joanna Briggs Institute critical appraisal instruments, appropriate for study type, were used to assess study quality and risk of bias. Descriptive characteristics and individual study results were presented followed by the synthesis for individual risk factors, also assessed using GRADE.

RESULTS

Fifty-eight individual eligible studies were grouped into six exposure topics: sociodemographic; antenatal and perinatal; maternal physical health; maternal mental health; environmental; genetic or biological studies. There were few eligible genetic studies. For half the topics, the certainty of evidence (GRADE) was moderate or high.

CONCLUSION

Multiple studies have examined individual potential determinants of ID, but few have investigated holistically to identify those populations most at risk. Our review would indicate that there are vulnerable groups where risk factors we identified, such as low socioeconomic status, minority ethnicity, teenage motherhood, maternal mental illness, and alcohol abuse, may cluster, highlighting a target for preventive strategies. At-risk populations need to be identified and monitored so that interventions can be implemented when appropriate, at preconception, during pregnancy, or after birth. This could reduce the likelihood of ID and provide optimal opportunities for vulnerable infants.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=120032], identifier [CRD42019120032].

Paternal and/or maternal preconception-induced neurobehavioral teratogenicity in animal and human models

Prenatal insult exposure effects on the offspring, have and are still considered the main interest of most teratological studies, while paternal and maternal preconception effects have received relatively little interest. Once thought to be a myth, paternal exposure to insults leading to numerous detrimental effects in the offspring, has been confirmed on several occasions and is gaining increased attention. These effects could be demonstrated molecularly, biochemically and/or behaviorally. Different epigenetic mechanisms have been proposed for these effects to occur, including DNA methylation, histone modification and sperm RNA transmission. Paternal insult exposure has been shown to cause several neurobehavioral and developmental defects in the offspring. Findings on parental insult exposure effects on the progeny will be discussed in this review, with the main focus being on neurobehavioral effects after parental preconceptional exposure. The exposure to the insults induced long-lasting, mostly marked, defects. A few pioneering, prevention and reversal studies were published. Interestingly, most studies were conducted on paternal exposure and, at the present state of this field, on animal models. Clinical translation remains the subsequent challenge.

How Family Histories Can Inform Research About Germ Cell Exposures: The Example of Autism

Throughout the scientific literature, heritable traits are routinely presumed to be genetic in origin. However, as emerging evidence from the realms of genetic toxicology and epigenomics demonstrate, heritability may be better understood as encompassing not only DNA sequence passed down through generations, but also disruptions to the parental germ cells causing de novo mutations or epigenetic alterations, with subsequent shifts in gene expression and functions in offspring. The Beyond Genes conference highlighted advances in understanding these aspects at molecular, experimental and epidemiological levels. In this commentary I suggest that future research on this topic could be inspired by collecting parents' germ cell exposure histories, with particular attention to cases of families with multiple children suffering idiopathic disorders. In so doing I focus on the endpoint of autism spectrum disorders (ASD). Rates of this serious neurodevelopment disability have climbed around the world, a growing crisis that cannot be explained by diagnostic shifts. ASD's strong heritability has prompted a research program largely focused on DNA sequencing to locate rare and common variants, but decades of this gene-focused research have revealed surprisingly little about the molecular origins of the disorder. Based on my experience as the mother of two children with idiopathic autism, and as a research philanthropist and autism advocate, I suggest ways researchers might probe parental germ cell exposure histories to develop new hypotheses that may ultimately reveal sources of non-genetic heritability in a subset of idiopathic heritable pathologies.