Folic Acid Supplementation in Spina Bifida Prophylaxis: Results from the Zurich Fetal Surgery Cohort

Introduction: Since preconceptional folic acid (FA) supplementation is known to reduce the risk of fetal spina bifida (fSB), the aim of this study was to systematically analyze the FA supplementation in a cohort of women with fSB repair in affected and subsequent pregnancies.

A total of 198 women, that underwent open fSB repair between 2010 and 2023, were compared in two groups (group 1 = correct FA and group 2 = incorrect FA preconceptionally) regarding maternal and fetal characteristics. Additionally, compliance to high dose FA supplementation in subsequent pregnancies was analyzed.

Sixty-five women (32.8%) had correct preconceptional FA supplementation (group 1), and 63 women (31.8%) had incorrect FA supplementation (group 2). The two groups did not significantly differ regarding maternal and fetal characteristics. Thirty-nine women had 48 subsequent pregnancies. FA was initiated prior to conception in 35 (72.9%) of these pregnancies, in 9 (18.7%) cases, FA supplementation was incorrect.

This study focuses on better awareness of FA supplementation as correct FA supplementation was low in women with fSB and suboptimal in high-risk situations after fSB pregnancies. However, these results also show that 1/2 of fSB occurs despite correct FA intake; thus, further research is needed to better understand the complex, multifactorial causes of this debilitating condition.