Chemical Factors that Cause Environmental Birth Defects
In women who drink during pregnancy, the alcohol can diffuse across the placenta to affect the fetus. The result is the fetal alcohol syndrome (FAS), with symptoms including-
- Small head and body
- Flattened face
- Distinctive eyes
- Retarded physical growth
- Mental retardation
- Low birth weight babies
- Heart defects
Active and/or passive smoking can lead to birth defects. Smoking especially after the first trimester of pregnancy is a major cause of premature births and the birth of underweight babies. Nicotine can cross the placenta and affect the fetus in the following ways-
- It speeds up the fetal heart and interrupts the baby’s respiratory movements.
- The amount of oxygen available to the fetus is reduced, which could slow tissue growth.
- It increases the chances of stillbirth and death of the baby in the first week following delivery.
The exact role of caffeine as to how it affects the unborn fetus is yet to be established. However, doctors suspect that caffeine creates changes in the fetal heartbeat and other functions. Animal studies have revealed that caffeine can cause deformities in skeletal and bone development.
Aspirin - Aspirin or drugs containing aspirin should be strictly avoided during the second half of pregnancy. Animal studies have indicated that aspirin may interfere with blood clotting in the fetus with potential for brain damage.
Barbituarates, amphetamines, tranquillizers, sleeping pills, diet pills, stimulants, antihistamines, valium should be avoided during pregnancy. These drugs can trigger a miscarriage or cause premature births.
Barbiturates can cause tremors, restlessness and irritability in the baby.
Thalidomide (tranquillizer) causes deformities of the arms and legs. Rarely, it can lead to defects of the heart, eyes, intestines, ears and kidneys.
Antibiotics- Some antibiotics should not be prescribed during pregnancy.
Tetracyclines- affect the growth of the baby’s bones. It can also cause yellow mottling and staining of the baby’s first teeth.
Streptomycin- can cause deafness in the baby.
Narcotics - Use of narcotics by the mother during her pregnancy increases the chances of premature birth and toxemia (poisons in the bloodstream).
Hallucinogens- These drugs affect the central nervous system of the fetus.