All the environmental causes that cause limb loss or deformity in children are called teratogens. Disadvantages of teratogens are-
(i) Intra-uterine growth restriction: Premature birth due to maternal malnutrition or lack of oxygen.
(ii) Macrosomia : In this disease the child is overweight and large in size. It is called big baby syndrome.
(iii) Smoking: The growth of the baby in the womb of a smoking mother is disturbed.
(iv) Alcohol consumption: Fetal alcohol syndrome occurs in the baby if the mother drinks alcohol.
(v) Food intake: Lack of nutritious food impairs fetal growth.
(vi) Mental condition: The mother’s mental condition needs to be good for the healthy development of the child.