Environmental causes of congenital anomalies, congenital infections
Environmental factors (also called teratogens) can be divided
into these groups: physical, chemical and biologic.
One of the most serious is ionizing radiation,
growth retardation and defects of the central nervous system.
Also it is necessary to mention the negative effects of vibrations.
- Pharmacs: cytostatics, antibiotics (especially tetracyclines and streptomycin),
hormones (progesteron, androgens), antiepileptics, anticoagulants etc.
- Drugs: alcohol — with a cca 40% probability, chronic alcohol
abuse during pregnancy causes fetal alcohol syndrome (characterised by brain
damage — microcephaly, hydrocephaly, leptomeningeal heterotopy,
corpus callosum agenesis, arinencephaly; heart defects — especially atrio-ventricular septal defects;
growth retardation, congenital malformations of eyes and joints.)
- LSD, marijuana
- Smoking: leads to disorders in afterbirth adaptation, lower birth weight
and increases the risk of pre-term delivery. Children whose mothers smoked during pregnancy
also develop asthma more often.
The fetus can be negatively affected by any illness the mother
undergoes during her pregnancy. Etiologic agents with the
most serious effects on the fetus are listed below (however,
the listing is not complete).
- Viruses: cytomegalovirus, herpes simplex, varicella-zoster, EBV, influenza, mumps
- Bacteria: treponema pallidum
- Parasites: toxoplasmosis