Birth Defects Are Preventable

Editorial 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: 1. Lethal if the defects (such as anencephaly or hypoplastic left heart syndrome) cause stillbirth (late fetal death) or infant death or pregnancies are terminated after the prenatal diagnosis of fetal defects in more than 50% of cases. 2. Severe if the defects (such as cleft lip or congenital pyloric stenosis) without medical intervention cause handicap or death. 3. Mild if defects (such as congenital dislocation of the hip or undescended testis) require medical intervention but life expectancy is good. 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 …