Folic acid supplementation in spina bifida prophylaxis: results from the Zurich fetal surgery cohort

Introduction Fetal spina bifida (fSB) is a neural tube defect that develops in very early pregnancy. Preconceptional folic acid (vitamin B9) supplementation is known to significantly reduce the risk of fSB. The goal of this study was to systematically analyze the folic acid supplementation in our cohort and their subsequent pregnancies and compare the outcome of women with and without folic acid supplementation before pregnancy.

Material/Method This is a retrospective single-center cohort study. Between 2010-2023, 200 patients underwent open fSB repair at our Center. Of these, 198 signed the informed consent and were included. Data was collected in a Redcap database. According to folic acid supplementation, patients were divided into two groups (group 1=yes; group 2=no). Baseline characteristics as well as the level of fetal lesion were compared between both groups. Additionally, the first 138 women operated at our center received a questionnaire to analyze subsequent pregnancies and the adherence to the strict folic acid supplementation recommendation, which was as follows: high dose folic acid (5mg) and the metabolized form (quatrefolic) for at least three months preconceptionally.

Results One hundred four women (52%) had folic acid supplementation, 27 (14%) had no supplementation and in 67 cases (34%) this information was missing. Group 1 and 2 did not significantly differ regarding baseline criteria and the level of fetal lesion. Twenty-five women had 28 subsequent pregnancies. Folic acid supplementation was initiated prior to conception in 22 (79%) pregnancies, in 3 (11%) with positive pregnancy test, in 1 (4%) no supplementation was taken and in 2 (7%) no data was available.

Discussion In this cohort of fSB repair about 50% of mothers took folic acid supplementation before pregnancy. In subsequent pregnancies preconceptional supplementation increased up to 80% but not as expected to 100%. This emphasizes the importance of prevention campaigns to ensure sufficient preconception folic acid supplementation.

Publication History

Article published online:
15 November 2023