The Relationship of Some Teratogenic Factors to the Birth of a Teratogenic Child

Abstract

A congenital malformation is an anatomical or structural abnormality present at birth. Congenital malformations may be caused by genetic factors or environmental insults or a combination of the two that occur during prenatal development. Most common congenital malformations demonstrate multifactorial inheritance with a threshold effect and are determined by a combination of genetic and environmental factors. During the first two weeks of gestation, teratogenic agents usually kill the embryo rather than cause congenital malformations. Major malformations are more common in early embryos than in newborns; however, most severely affected embryos are spontaneously aborted during the first six to eight weeks of gestation. Teratology is  the  science  that  investigates  the  congenital  malformations  and  their causes. Intrauterine exposure to a toxicant, particularly in early pregnancy, induces embryonic and fetal changes ranging from none up to malformations and stillbirths. The  teratogenic  agents  include  some  viral,  spirochetal  and  protozoal  infections, physical  agents  as  ionizing  radiations  and  excessive  heat,  pharmacological  drugs as  thalidomide,  excessive  vitamin  A,  corticosteroids,  antiepileptic,  antimalarial, anti leishmaniasis  and  antihypertensive  agents,  industrial  pollutants  as  toluene  and cadmium, alcohol and smoking abuse, and narcotics. Maternal health problems as diabetes mellitus, multiple sclerosis and rheumatoid arthritis may also add to the etiology  list  of  teratogenesis. The  prevalence  of the  congenital birth  defects ranges from 2 to 5% throughout the first year of postnatal life in this study, about 170 cases were collected from the questionnaire in an attempt to study the factors causing the birth of a teratogenic child and the diseases and deformities that result from it. It was found that many medications and chemicals that the mother is exposed to during pregnancy cause the birth of a teratogenic child.