16 January 2017
Int J Med Sci 2005; 2(3):91-92. doi:10.7150/ijms.2.91
Birth Defects Are Preventable
Foundation for the Community Control of Hereditary Diseases, Budapest, Hungary
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How to cite this article:
Czeizel AE. Birth Defects Are Preventable. Int J Med Sci 2005; 2(3):91-92. doi:10.7150/ijms.2.91. Available from http://www.medsci.org/v02p0091.htm
Birth defects – or by according to the World Health Organization's (WHO) term: congenital anomalies – are structural, functional and/or biochemical-molecular defects present at birth whether detected at that time or not (Figure 1). Among different categories of birth defects, congenital abnormalities, i.e. structural-morphological defects represent the largest one.
Congenital abnormalities can be divided into three groups:
Lethal and severe defects together constitute major congenital abnormalities.
Minor anomalies or morphological variants (such as epicanthal folds, ocular hypotelorism, preauricular tags and pits, low-set ears, simian crease, clino- and camptodactyly, partial syndactyly between toes 2 and 3, hydrocele, umbilical hernia, sacral dimple, etc) without serious medical or cosmetic consequences are excluded from the category of congenital abnormalities.
In general we cannot measure the incidence of congenital abnormalities due to the prenatal loss of fetuses such as blighted ova, miscarriages and ectopic pregnancies. Thus we used the term birth (live- and stillbirths) prevalence in the past. However, recently the different methods of prenatal diagnoses have been used widely for the detection of fetal defects and pregnancies are frequently terminated if the fetus is severely affected. Thus, the rate of defects is calculated for informative offspring including (i) live born infants, (ii) stillborn fetuses, and (iii) prenatal diagnosed and terminated affected fetuses and the term total (birth and fetal) prevalence of congenital abnormalities is used. Of course, the total prevalence of congenital abnormalities depends on the spectrum of congenital abnormalities evaluated, the period of study (only at birth or in early neonatal period or prenatal or the whole infant period are included), the completeness of ascertainment, the diagnostic skill of experts, demographic and genetic characteristics of the study population, etc. In Hungary the total prevalence of congenital abnormalities was 66.83 per 1000 informative offspring in the 1980s and within this, the total rate of major congenital abnormalities was 27.01 per 1000 informative offspring [1,2].
The causes of congenital abnormalities can be classified into three main groups:
Congenital abnormalities have two main medical characteristics: (i) defect conditions with a limited chance for complete recovery and (ii) the earliest (fetal-birth) onset. Thus, there is only one optimal medical solution and it is the prevention.
Prevention approaches are often classified into three levels:
Thus, there are two main conclusions: at present the major part of congenital abnormalities (85.3%) are preventable; however, different congenital abnormalities do not represent a single pathological entity and therefore there is no single strategy for their prevention.
Conflict of interest
The author has declared that no conflict of interest exists.
1. Czeizel AE, Intődy Z, Modell B. What proportion of congenital abnormalities can be prevented?. Brit Med J. 1996 ;306:499-503
2. Czeizel AE. Prevention of developmental abnormalities with particular emphasis of primary prevention. Tsitologija i Genetika. 2002 ;36:56-71
Andrew E. Czeizel Foundation for the Community Control of Hereditary Diseases, 1148 Budapest, Bolgárkerék utca 3. Hungary