Folic acid antagonist use before and during pregnancy and risk for selected birth defects

Maternal exposure to folate antagonists and susceptibility to congenital heart disease in offspring: A systematic review and meta-analysis

AIMS

The objective of this meta-analysis was to determine whether maternal exposure to folate antagonists is associated with increased rates of congenital heart disease in offspring.

METHODS

A comprehensive search for articles in the MEDLINE (PubMed) and EMBASE databases published up to 21 August 2023 was performed. The search strategy was not limited by study design but only for articles in the English language.

RESULTS

Analysis of 6 cohort studies and 5 cross-sectional studies, published between 1976 and 2020, showed significant increase in rate of congenital heart disease (odds ratio 1.55, 95% confidence interval, 1.28-1.87) when exposed to folate antagonists compared with the control. Further subgroup analysis showed the increased rate for exposure to both dihydrofolate reductase inhibitors and antiepileptic drugs separately. No differences were observed when analyses were stratified by timing of study.

CONCLUSION

Administration of folate antagonists within the 12-week period preceding conception and throughout the second and third months of gestation exhibited a statistically significant elevation in the susceptibility to congenital heart diseases. Notably, the protective effect of folic acid supplementation was reported in cases of congenital heart disease linked to dihydrofolate reductase inhibitors but not that associated with antiepileptic drugs.

Advances in Fetal Surgical Repair of Open Spina Bifida

Spina bifida remains a common congenital anomaly of the central nervous system despite national fortification of foods with folic acid, with a prevalence of 2-4 per 10,000 live births. Prenatal screening for the early detection of this condition provides patients with the opportunity to consider various management options during pregnancy. Prenatal repair of open spina bifida, traditionally performed by the open maternal-fetal surgical approach through hysterotomy, has been shown to improve outcomes for the child, including decreased need for cerebrospinal fluid diversion surgery and improved lower neuromotor function. However, the open maternal-fetal surgical approach is associated with relatively increased risk for the patient and the overall pregnancy, as well as future pregnancies. Recent advances in minimally invasive prenatal repair of open spina bifida through fetoscopy have shown similar benefits for the child but relatively improved outcomes for the pregnant patient and future childbearing.

Multifactorial Rare Diseases: Can Uncertainty Analysis Bring Added Value to the Search for Risk Factors and Etiopathogenesis?

Uncertainty analysis is the process of identifying limitations in knowledge and evaluating their implications for scientific conclusions. Uncertainty analysis is a stable component of risk assessment and is increasingly used in decision making on complex health issues. Uncertainties should be identified in a structured way and prioritized according to their likely impact on the outcome of scientific conclusions. Uncertainty is inherent to the rare diseases (RD) area, where research and healthcare have to cope with knowledge gaps due to the rarity of the conditions; yet a systematic approach toward uncertainties is not usually undertaken. The uncertainty issue is particularly relevant to multifactorial RD, whose etiopathogenesis involves environmental factors and genetic predisposition. Three case studies are presented: the newly recognized acute multisystem inflammatory syndrome in children and adolescents associated with SARS-CoV-2 infection; the assessment of risk factors for neural tube defects; and the genotype-phenotype correlation in familial Mediterranean fever. Each case study proposes the initial identification of the main epistemic and sampling uncertainties and their impacts. Uncertainty analysis in RD may present aspects similar to those encountered when conducting risk assessment in data-poor scenarios; therefore, approaches such as expert knowledge elicitation may be considered. The RD community has a main strength in managing uncertainty, as it proactively develops stakeholder involvement, data sharing and open science. The open science approaches can be profitably integrated by structured uncertainty analysis, especially when dealing with multifactorial RD involving environmental and genetic risk factors.