Abnormal Development - Folic Acid and Neural Tube Defects
|Embryology - 22 Jul 2017 Expand to Translate|
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- 1 Introduction
- 2 Some Recent Findings
- 3 Neural Tube Closure
- 4 Neural Tube Defect Classification
- 5 Australian Statistics
- 6 USA Statistics
- 7 Folic Acid
- 8 Folate Supplementation and Other Abnormalities
- 9 Surgery for Spina Bifida
- 10 References
- 11 External Links
- 12 Glossary Links
In 2001, the Australian estimated birth prevalence of neural tube defects was 0.5 per 1,000 births (National Perinatal Statistics Unit). Low maternal dietary folic acid (folate) has been shown to be associated with the development of neural tube defects. In September 2009, mandatory folic acid fortification of bread flour was introduced in Australia.
Research over the last 20 years had suggested a relationship between maternal diet and the birth of an affected infant. Recent evidence has confirmed that folic acid, a water soluble vitamin (vitamin B9) found in many fruits (particularly oranges, berries and bananas), leafy green vegetables, cereals and legumes, may prevent the majority of neural tube defects.
In the U.S.A., the Food and Drug Administration in 1996 authorized that all enriched cereal grain products be fortified with folic acid, with optional fortification beginning in March 1996 and mandatory fortification in January 1998.
In Australia, from 2009 the mandatory folic acid fortification standard required addition of folic acid to all wheat flour for bread making, with the exception of organic bread, within the prescribed range of 200–300 μg per 100 g of flour.
The March of Dimes Folic Acid Campaign (a major US charity group) has as one of its major objectives to reduce neural tube defects by 30% by 2001 using community programs, professional education, and mass media information.
- Links: Nutrition | Folate Deficiency | Iodine Deficiency | Neural System - Abnormalities | Axial Skeleton Abnormalities
Some Recent Findings
|More recent papers|
This table shows an automated computer PubMed search using the listed sub-heading term.
References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.
Paul I Heidekrueger, Myat Thu, Wolfgang Mühlbauer, Charlotte Holm-Mühlbauer, Philippe Schucht, Hans Anderl, Heinrich Schoeneich, Kyawzwa Aung, Mg Mg Ag, Ag Thu Soe Myint, Sabrina Juran, Thiha Aung, Denis Ehrl, Milomir Ninkovic, P Niclas Broer Safe and sustainable: the extracranial approach toward frontoethmoidal meningoencephalocele repair. J Neurosurg Pediatr: 2017;1-7 PubMed 28731403
Micah M Simpamba, Patricia M Struthers, Margaret M Mweshi Access to health care for children with neural tube defects: Experiences of mothers in Zambia. Afr J Disabil: 2016, 5(1);267 PubMed 28730060
Derya Başbuğ, Alper Başbuğ, Cavidan Gülerman Is unexplained elevated maternal serum alpha-fetoprotein still important predictor for adverse pregnancy outcome? Ginekol. Pol.: 2017, 88(6);325-330 PubMed 28727133
Desirée Valera-Gran, Eva M Navarrete-Muñoz, Manuela Garcia de la Hera, Ana Fernández-Somoano, Adonina Tardón, Jesús Ibarluzea, Nekane Balluerka, Mario Murcia, Llúcia González-Safont, Dora Romaguera, Jordi Julvez, Jesús Vioque, INMA Project Effect of maternal high dosages of folic acid supplements on neurocognitive development in children at 4-5 years of age: the prospective birth cohort Infancia y Medio Ambiente (INMA) study. Am. J. Clin. Nutr.: 2017; PubMed 28724645
Adalisa Ponzano, Gian Mario Tiboni Folate serum levels in Italian women entering an in vitro fertilization program. Gynecol. Endocrinol.: 2017;1-3 PubMed 28723303
Neural Tube Closure
| This cartoon movie shows a dorsolateral view (from the back left side) of the early embryo.
Neural Tube Defect Classification
Neural tube defects comprise three distinct conditions: anencephaly, spina bifida and encephalocele. Note that the current ICD10 classification system is being updated to ICD11 that is currently in beta testing status. The data on this page, other than the information table below, is from ICD10 classification.
|International Classification of Diseases ICD-11 Beta Draft - 20 Developmental anomalies|
| ICD-11 Beta Draft - NOT FINAL, updated on a daily basis, It is not approved by WHO, NOT TO BE USED for CODING except for agreed FIELD TRIALS.
Chapter 20 Developmental anomalies, only a few examples of the draft ICD-11 Beta coding and tree structure for "structural developmental anomalies" within this section are shown in the table below.
|Mortality and Morbidity Statistics - 20 Developmental Anomalies|
| Structural Developmental Anomalies
|Multiple developmental anomalies or syndromes|
|Chromosomal anomalies, excluding gene mutations|
|Conditions with disorders of intellectual development as a relevant clinical feature|
| LD6Y Other specified developmental anomalies
LD6Z Developmental anomalies, unspecified
| CD-11 Beta Draft - NOT FINAL, updated on a daily basis, It is not approved by WHO, NOT TO BE USED for CODING except for agreed FIELD TRIALS.
- A congenital anomaly characterised by the total or partial absence of the cranial vault, the covering skin and the brain.
- Remaining brain tissue may be very much reduced in size.
- Craniorachischisis and iniencephaly are included.
- Acephaly, the absence of the head observed in amorphous acardiac twins, is excluded.
|International Classification of Diseases (ICD-10) - Anencephaly|
ICD-10 codes: Q00 Anencephaly and similar malformations
- A congenital anomaly characterised by a failure in the closure of the spinal column.
- Characterised by herniation or exposure of the spinal cord and/or meninges through the incompletely closed spine.
- This excludes spina bifida occulta and sacrococcygeal teratoma without dysraphism.
- ICD codes: ICD-9-BPA codes: 741.00–741.99 or ICD-10-AM codes: Q05.0–Q05.9.
|International Classification of Diseases (ICD-10) - Spina bifida|
Q05 Spina bifida
Incl.: hydromeningocele (spinal), meningocele (spinal), meningomyelocele, myelocele, myelomeningocele, rachischisis, spina bifida (aperta)(cystica), syringomyelocele Excl.: Arnold-Chiari syndrome (Q07.0), spina bifida occulta (Q76.0)
- A congenital anomaly characterised by herniation of the brain and/or meninges through a defect in the skull.
- ICD codes: ICD-9-BPA codes: 742.00–742.09 or ICD-10-AM codes: Q01.0–Q01.2, Q01.8, Q01.9.
From 13 September 2009, the mandatory folic acid fortification standard requires the addition of folic acid to all wheat flour for bread making, with the exception of organic bread, within the prescribed range of 200–300 μg per 100 g of flour.
A recent 2016 study has shown since fortification:
- Overall decrease in the rate of neural tube defects (NTDs) by 14.4%
- Teenagers the rate of NTDs decreased by almost 55%
- Aboriginal and Torres Strait Islander women the rate of NTDs decreased by 74%
An earlier 2011 study looking at the prevalence of neural tube defects before mandatory fortification.
- Women who have one infant with a neural tube defect have a significantly increased risk of recurrence
- 40-50 per thousand compared with 2 per thousand for all births.
- A randomised controlled trial conducted by the Medical Research Council of the United Kingdom demonstrated a 72% reduction in risk of recurrence by periconceptional (ie before and after conception) folic acid supplementation (4mg daily).
- Other epidemiological research, including work done in Australia, suggests that primary occurrences of neural tube defects may also be prevented by folic acid either as a supplement or in the diet.
- This has been confirmed in a randomised controlled trial from Hungary, which found that a multivitamin supplement containing 0.8mg folic acid was effective in reducing the occurrence of neural tube defects in first births.
Before mandatory folic acid fortification was introduced:
- mean dietary folic acid intakes for women aged 16–44 years (the target population) in Australia was 108 micrograms (μg) of folic acid per day and in New Zealand was 62 μg of folic acid per day, well below the recommended 400 μg per day.
- there were 149 pregnancies affected by NTDs in 2005 in Australia (rate of 13.3 per 10,000 births) in the three states that provide the most accurate baseline of NTD incidence (South Australia, Western Australia and Victoria), and 63 pregnancies affected by NTDs in 2003 in New Zealand (rate of 11.2 per 10,000 births).
Before mandatory iodine fortification was introduced:
- large proportions of the Australian and New Zealand population had inadequate iodine intakes.
- national surveys measuring median urinary iodine concentration (MUIC) in schoolchildren, an indicator of overall population status, confirmed mild iodine deficiency in both countries.
- The concentration was 96 μg per litre in Australia, and 66 μg per litre in New Zealand, less than the 100–200 μg per litre considered optimal.
- Links: Folic Acid and Neural Tube Defects | Iodine Deficiency | Australian Statistics | AIHW - folic acid and iodine
In the U.S.A. the Food and Drug Administration in 1996 authorized that all enriched cereal grain products be fortified with folic acid, with optional fortification beginning in March 1996 and mandatory fortification in January 1998. The data below shows the subsequent changes in anencephaly and spina bifida rate over that period.
Data CDC Report
Alternate Names: Folic acid, Folate, Pteroylglutamic acid
(Data from KEGG)
Folate Supplementation and Other Abnormalities
A recent study of periconceptional folate supplementation using the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2010) identified no statistically significant evidence of any effects on prevention of cleft palate, cleft lip, congenital cardiovascular defects, miscarriages or any other birth defects.
Surgery for Spina Bifida
The neural tube remaining open during fetal development can lead to neural damage through exposure to amniotic fluid and mechanical effects. There are experimental fetal surgical techniques in some countries that allow prenatal repair and perhaps prevent further neurological damage. There are though fetal and maternal risks associated with this surgical procedure. A recent 2014 Cochrane Database study identified that "insufficient evidence to recommend drawing firm conclusions on the benefits or harms of prenatal repair as an intervention for fetuses with spina bifida."
The surgical repair after birth is a more common procedure.
- AIHW 2016. Monitoring the health impacts of mandatory folic acid and iodine fortification 2016. Cat. no. PHE 208. Canberra: AIHW. PDF
- NaTasha D Hollis, Emily G Allen, Tiffany Renee Oliver, Stuart W Tinker, Charlotte Druschel, Charlotte A Hobbs, Leslie A O'Leary, Paul A Romitti, Marjorie H Royle, Claudine P Torfs, Sallie B Freeman, Stephanie L Sherman, Lora J H Bean Preconception folic acid supplementation and risk for chromosome 21 nondisjunction: a report from the National Down Syndrome Project. Am. J. Med. Genet. A: 2013, 161A(3);438-44 PubMed 23401135
- Pål Surén, Christine Roth, Michaeline Bresnahan, Margaretha Haugen, Mady Hornig, Deborah Hirtz, Kari Kveim Lie, W Ian Lipkin, Per Magnus, Ted Reichborn-Kjennerud, Synnve Schjølberg, George Davey Smith, Anne-Siri Øyen, Ezra Susser, Camilla Stoltenberg Association between maternal use of folic acid supplements and risk of autism spectrum disorders in children. JAMA: 2013, 309(6);570-7 PubMed 23403681 | JAMA
- Marina S Lee, Jenna R Bonner, David J Bernard, Erica L Sanchez, Eric T Sause, R Reid Prentice, Shawn M Burgess, Lawrence C Brody Disruption of the folate pathway in zebrafish causes developmental defects. BMC Dev. Biol.: 2012, 12;12 PubMed 22480165
- Simonette R Mallard, Andrew R Gray, Lisa A Houghton Periconceptional bread intakes indicate New Zealand's proposed mandatory folic acid fortification program may be outdated: results from a postpartum survey. BMC Pregnancy Childbirth: 2012, 12;8 PubMed 22333513
- Macaldowie, A. and Hilder, L. (2011) Neural tube defects in Australia: prevalence before mandatory folic acid fortification. Cat. no. PER 53. Canberra: AIHW.
- CDC Trends in Spina Bifida and Anencephalus in the United States, 1991-2005
- Luz Maria De-Regil, Ana C Fernández-Gaxiola, Therese Dowswell, Juan Pablo Peña-Rosas Effects and safety of periconceptional folate supplementation for preventing birth defects. Cochrane Database Syst Rev: 2010, (10);CD007950 PubMed 20927767
- N Scott Adzick Fetal surgery for spina bifida: past, present, future. Semin. Pediatr. Surg.: 2013, 22(1);10-7 PubMed 23395140
- Rosalie M Grivell, Chad Andersen, Jodie M Dodd Prenatal versus postnatal repair procedures for spina bifida for improving infant and maternal outcomes. Cochrane Database Syst Rev: 2014, 10;CD008825 PubMed 25348498
Paul W Veenboer, J L H Ruud Bosch, Floris W A van Asbeck, Laetitia M O de Kort Upper and lower urinary tract outcomes in adult myelomeningocele patients: a systematic review. PLoS ONE: 2012, 7(10);e48399 PubMed 23119003
Monika Eichholzer, Otmar Tönz, Roland Zimmermann Folic acid: a public-health challenge. Lancet: 2006, 367(9519);1352-61 PubMed 16631914
Tsunenobu Tamura, Mary Frances Picciano Folate and human reproduction. Am. J. Clin. Nutr.: 2006, 83(5);993-1016 PubMed 16685040
Shi Wu Wen, Mark Walker An exploration of health effects of folic acid in pregnancy beyond reducing neural tube defects. J Obstet Gynaecol Can: 2005, 27(1);13-9 PubMed 15937577
Anne M Molloy Folate bioavailability and health. Int J Vitam Nutr Res: 2002, 72(1);46-52 PubMed 11887752
L E Daly, P N Kirke, A Molloy, D G Weir, J M Scott Folate levels and neural tube defects. Implications for prevention. JAMA: 1995, 274(21);1698-702 PubMed 7474275
I Leck Folates and the fetus. Lancet: 1977, 1(8021);1099-100 PubMed 68194
R W Smithells, S Sheppard, C J Schorah Vitamin dificiencies and neural tube defects. Arch. Dis. Child.: 1976, 51(12);944-50 PubMed 1015847
- Folic Acid Supplementation for the Prevention of Neural Tube Defects An Update of the Evidence for the U.S. Preventive Services Task Force
- Screening for Neural Tube Defects— Including Folic Acid/Folate Prophylaxis Guide to Clinical Preventive Services, 2nd Edition: 1996
External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.
- Australia Department of Health Nutrition and Healthy Eating Trends in Neural Tube Defects in Australia
- See also the NHMRC Publication Dietary Folic Acid and Neural Tube Defects
- National Perinatal Statistics Unit
- Australian Journal of Nutrition and Dietetics
- Australian Nutrition Foundation
- CSIRO Human Nutrition
- Food, Nutrition & Health Information - Centre for Advanced Food Research
- Office of Dietary Supplements, National Institutes of Health (USA)Dietary Supplement Fact Sheet: Folate
- Healthy Eating, Healthy Living
- AIS Sport Nutrition - information from the Australian Institute of Sport. Supplies nutrition research, a question-and-answer section, publications, and other resources.
- America's Eating Habits - a report from the U.S. Department of Agriculture's economic research service. Covers dietary recommendations, health claims in food advertising, reality about cholesterol, and various other topics.
- British Nutrition Foundation - an organization that works with academic, private, and public groups on nutrition. Includes nutrition education, facts, news, and publications.
- Center for Food Safety & Applied Nutrition - a repository of links relevant to all manner of food issues, including food safety. Emphasizes FDA regulations and related research programs.
- Nutrition.gov - a collection of information and links to other sites on food safety, food programs, and federally funded research centers.
- Nutrition.org - site of the American Society for Nutritional Sciences. Features an encyclopedia that summarizes food sources, diet recommendations, and deficiencies for a number of macro- and micronutrients.
- Nutrition Navigator - a guide to nutrition websites reviewed and rated by Tufts University nutritionists. Supplies news and sections arranged by topic.
- U.S. Department of Agriculture
- Children's Nutrition Research Center
- Facts about the DASH Diet
- Healthfinder Kids
- Interactive Healthy Eating Index
- National Dairy Council
- Nutrition Explorations
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