Teratogens
Teratogens----agents and conditions, including viruses, drugs, chemicals, stressors, and malnutrition, which can impair prenatal development and lead to birth defects or even death
Behavioral teratogens---teratogens that tend to harm the prenatal brain, affecting the future child’s intellectual and emotional functioning.
à although all teratogens increase the risk of harm to the developing child, none always cause damage; the ultimate impact depends on the complex interplay of many factors
Factors influencing the effect of teratogens
à some teratogens cause damage only during specific days or weeks in early pregnancy
à other teratogens are harmful at any time during the pregnancy---for example, for behavioral teratogens, there is no safe period---the brain and nervous system can be harmed throughout the pregnancy
critical period---in prenatal development, the time when a particular organ or other body part is most susceptible to teratogenic damage
Threshold effect---the phenomenon in which a particular teratogen is relatively harmless in small doses but becomes harmful when exposure reaches a certain level (the threshold)
Interaction effect---the phenomenon in which a particular teratogen’s potential for causing harm increases when it is combined with another teratogen or another risk factor
à possessing and not possessing certain genes may make the developing child more susceptible to the effect of a teratogen
Examples of Teratogens
A)Diseases (Maternal Illness)
1. Rubella---a viral disease, if contracted early during pregnancy, can harm the fetus
à causes blindness, deafness, and damage to the central nervous system
B) Drugs (Medications or Social Drugs)
Medicinal drugs---these are drugs that remedy problems in a person’s body that in some cases have teratogenic effect
à i.e., tetracycline, acne medication, aspirin, antacids, diet pills
Psychoactive drugs---drugs that affect how the mind works
à i.e, alcohol, tobacco, marijuana, cocaine, heroine
à all psychoactive drugs slow down fetal growth and increase the risk of premature labor
Fetal Alcohol Syndrome (FAS)---a cluster of birth defects, including abnormal facial characteristics, slow physical growth, and retarded mental development
à these birth defects are caused by the mother’s drinking excessive quantities of alcohol when pregnant
C) Environmental Toxins