Birth defects are preventable[1]

Birth defects - or by according to the World Health Organization’s term: congenital anomalies - are structural, functional and/or biochemical-molecular defects present at birth whether detected at that time or not. Among different categories of birth defects, congenital abnormalities (CAs), i. e. structural-morphological defects represent the largest one.

CAs have two main characteristics: (i) defect conditions with a limited chance for complete recovery and (ii) the earliest (fetal or birth) onset. Thus, there is only one optimal medical solution for CAs and this is prevention. It is worth differentiating three levels of prevention (Tab. [1]), however, the efficacy of primary prevention was limited before 1990 [1].

There was a breakthrough in the primary prevention of CAs in the 1990 s and it was connected with the introduction of periconceptional folic acid or folic acid-containing multivitamin supplementation. First the prevention of recurrent neural-tube defects (NTD) by a folic acid (0.36mg)-containing multivitamin preparation used during at least one month before and three months after conception (i. e. periconceptional period) was shown in a non-randomized intervention study (Tab. [2]) [2] [3]. However, the results of this study were not accepted by some experts due to the possible social selection. Thus, the Medical Research Council (UK) organized a multicenter international randomized controlled trial (RCT) in which 43 % of participants came from Hungary. This trial indicated the efficacy of a large pharmacological dose (4 mg) of folic acid in the prevention of recurrent NTD (Tab. [2]) [4].

Table 1 Prevention of congenital abnormalities (CAs) Primary: avoidance of the causes of CAs- rubella vaccination- avoidance of teratogens (alcohol, drug, diabetes)- genetic counselling (reduction of recurrent CAs) Secondary: early detection and medical treatment- neonatal PKU, etc. and orthopaedic screening- prenatal diagnosis and selective abortion (?) = chromosomal aberrations, gene mutations, CAs- specific postnatal treatment = undescended testis, patent ductus arteriosus Tertiary: early surgical correction without residual effect e. g., cardiovascular CAs, pyloric stenosis, etc.

Table 2 Data and results of previous intervention studies for the reduction of recurrent NTD Type Method Location Supplement Risk Reduction Recurrence non-randomized Yorkshire 2 North. Ireland 3 Multivitamin(0.36 mg Folic Acid) 91 %83 % randomized Multicenter MRC 4 Folic Acid (4.0 mg) 71 %

1 Summary of a lecture held at the 9th symposium of Gesellschaft für angewandte Vitaminforschung e.V. - GVF. Bonn, 28.06.2006.

References

• 1 Czeizel A E, Intödy Z S, Modell B. What proportion of congenital abnormalities can be prevented?.  BMJ. 1993;  306 499-503.
• 2 Smithells R W, Sheppard S, Wild J, Schorah C J. Prevention of neural tube defect recurrences in Yorkshire: final report.  Lancet. 1989;  ii (8661) 498-499.
• 3 Nevin N C, Seller M J. Prevention of neural-tube-defect recurrences.  Lancet. 1990;  335 178-179.
• 4 MCR Vitamin Study Research Group. Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. Lancet 1991 338: 131-137.
• 5 Czeizel A E. Ten years of experience in periconceptional care.  Eur J Obstet Gynecol Reprod Biol. 1999;  84 43-49.
• 6 Czeizel A E, Dudás I. Prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation.  N Engl J Med. 1992;  327 1832-1835.
• 7 Czeizel A E. Prevention of congenital abnormalities by periconceptional multivitamin supplementation.  BMJ. 1993;  306 1645-1648.
• 8 Czeizel A E. Reduction of urinary tract and cardiovascular defects by periconceptional multivitamin supplementation.  Am J Med Genet. 1996;  62 179-183.
• 9 Czeizel A E, Dobo M, Vargha P. Hungarian cohort controlled trial of periconceptional multivitamin supplementation shows reduction in certain congenital abnormalities.  Birth Defects Res A Clin Mol Teratol. 2004;  70 853-861.
• 10 Botto L D, Olney R S, Erickson J D. Vitamin supplements and the risk for congenital anomalies other than neural tube defects.  Am J Med Genet C Semin Med Genet. 2004;  125 12-21.
• 11 Czeizel A E, Timár I, Sárközi A. Dose-dependent effect of folic acid on the prevention of orofacial clefts.  Pediatrics. 1999;  104 e66.
• 12 Taruscio D. (Ed.) .Folic Acid: from Research to Public Health Practice. Rapporti ISTISAN Roma; 2004: 26.

1 Summary of a lecture held at the 9th symposium of Gesellschaft für angewandte Vitaminforschung e.V. - GVF. Bonn, 28.06.2006.