Our Life

Congenital abnormalities are defined as malformations which are present birth due to factors which have affected the fetus’ development. These malformations can be found anywhere on the baby but the most common organs affected are the heart, brain and limbs (Thein et al 1992). Congenital malformations affecting the heart are seen to be the most deadly; around 50% of deaths due to congenital malformations are due to malformations of the heart (Yang et al 1997). The causes of congenital abnormalities can be classified into 4 groups – genetic, environmental, multifactorial (combination of genetic and environmental factors) and unknown. Up to 60% of congenital abnormalities are still caused by unknown factors. Only around 10% of malformations have been recognized as having an environmental basis. Environmental factors are classed as teratogens and several groups of exist; infection (rubella virus, herpes), radiation (nuclear bombs, radiation therapy), metabolic (diabetes, folic-acid deficiency) and drugs (ecstasy, isotretinoin, alcohol). Different environmental teratogens will cause different effects through different mechanisms. The fetus will also have ‘most-susceptible-periods’ to each teratogen depending on the organs it effects. As a general rule the most susceptible period for the fetus is during the first eight weeks of development as the most important developmental processes are taking place at this time (Finnell et al. 2002). This report will focus on a common environmental teratogen, folic-acid deficiency, and will investigate the mechanisms with which it effects fetal development.

Folic-acid deficiency