Guideline No. 410: Prevention, Screening, Diagnosis, and Pregnancy Management for Fetal Neural Tube Defects

Abstract

Objective: This revised guideline is intended to provide an update on the genetic aspects, prevention, screening, diagnosis, and management of fetal neural tube defects.

Target population: Women who are pregnant or may become pregnant. Neural tube defect screening should be offered to all pregnant women.

Options: For prevention: a folate-rich diet, and folic acid and vitamin B₁₂ supplementation, with dosage depending on risk level. For screening: second-trimester anatomical sonography; first-trimester sonographic screening; maternal serum alpha fetoprotein; prenatal magnetic resonance imaging. For genetic testing: diagnostic amniocentesis with chromosomal microarray and amniotic fluid alpha fetoprotein and acetylcholinesterase; fetal exome sequencing. For pregnancy management: prenatal surgical repair; postnatal surgical repair; pregnancy termination with autopsy. For subsequent pregnancies: prevention and screening options and counselling.

Outcomes: The research on and implementation of fetal surgery for prenatally diagnosed myelomeningocele has added a significant treatment option to the previous options (postnatal repair or pregnancy termination), but this new option carries an increased risk of maternal morbidity. Significant improvements in health and quality of life, both for the mother and the infant, have been shown to result from the prevention, screening, diagnosis, and treatment of fetal neural tube defects.

Benefits, harms, and costs: The benefits for patient autonomy and decision-making are provided in the guideline. Harms include an unexpected fetal diagnosis and the subsequent management decisions. Harm can also result if the patient declines routine sonographic scans or if counselling and access to care for neural tube defects are delayed. Cost analysis (personal, family, health care) is not within the scope of this clinical practice guideline.

Evidence: A directed and focused literature review was conducted using the search terms spina bifida, neural tube defect, myelomeningocele, prenatal diagnosis, fetal surgery, neural tube defect prevention, neural tube defect screening, neural tube defect diagnosis, and neural tube defect management in order to update and revise this guideline. A peer review process was used for content validation and clarity, with appropriate ethical considerations.

Validation methods: The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

Intended audience: Maternity care professionals who provide any part of pre-conception, antenatal, delivery, and neonatal care. This guideline is also appropriate for patient education. RECOMMENDATIONS (GRADE RATINGS IN PARENTHESES).

Keywords: fetal surgery; myelomeningocele; neural tube defect diagnosis; neural tube defect management; neural tube defect prevention; neural tube defect screening; neural tube defects; prenatal diagnosis; spina bifida.