Folic acid supplementation in Spina bifida prophylaxis: Results from the Zurich fetal surgery cohort

Since preconceptional folic acid (FA) supplementation is known to reduce the risk of fetal spina bifida (fSB), aim of this study was to systematically analyze the FA supplementation in a cohort of women with fSB repair in affected and subsequent pregnancies. 198 women, that underwent open fSB repair between 2010-2023, 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.