When do teratogens have the greatest effect

Cockroft, David L. Cohlan, Sidney Q. Dareste, Camille. Paris: E. Edwards, Marshall J. Finnell, Richard H. Friedman, Jan M. Garfield, Eugene. Philadelphia: ISI Press, , — Germain, Mary-Ann, William S. Webster, and Marshall J. Goldstein, Leopold and Douglas P. Graham Jr. Edwards, and Marshall J. Gregg, Norman McAlister. Hale, Fred. Hellmann, Wilhelmine. Hill, Robert. Kalter, Harold. Lary, Joseph M.

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Warkany, Josef, Rose C. Nelson, and Elizabeth Scraffenberger. Wilson, James G. Environment and Birth Defects. James G. Wilson and Frank Clarke Fraser, Vol. New York: Plenum Press, , 47— Zuck, Michael V. Brigham Narins. Detroit: Gale, , —8. Printer-friendly version PDF version. Teratogenic agents include infectious agents rubella, cytomegalovirus, varicella, herpes simplex, toxoplasma, syphilis, etc.

Common teratogens include some medications, recreational drugs, tobacco products, chemicals, alcohol, certain infections, and in some cases, uncontrolled health problems in the birthing parent. Alcohol is a well-known teratogen that can cause harmful effects on the fetus after exposure at any time during pregnancy. The most common malformations include craniofacial dysmorphisms, cleft palate, thymic aplasia, and neural tube defects. The tranquilizer thalidomide is one of the most famous and notorious teratogens.

However, a direct teratogenic effect from influenza viruses appears to be unlikely, and we suggest that the higher prevalence of the CAs indicated above can be explained mainly by fever, because this risk was reduced by the use of antifever drugs. Viruses rarely cross the placental barrier, but when the virus does reach the fetus, it can result in severe birth defects such as microcephaly or even fetal death. Five viruses are known to be teratogenic in humans: cytomegalovirus, rubella, herpes simplex, Venezuelan equine encephalitis, and varicella viruses.

According to the report, Sudan has the most birth defects, with 82 per 1, live births, compared with American Indians had the highest rates of lethal birth defects, followed by Asians, Hispanics, and blacks. Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Term Paper When do teratogens have the greatest effects? Term Paper. Ben Davis February 26, When do teratogens have the greatest effects?

Once the fertilized egg is attached to the uterus, the mother and the embryo share a blood supply. Chemicals in the mother's blood can then affect the growing baby. For example, the neural tube closes in the first 3 to 5 weeks of the pregnancy. During this time, teratogens can cause neural tube defects such as spina bifida. Some organs are sensitive to teratogens during the whole pregnancy.

This includes the baby's brain and spinal cord. Alcohol affects the brain and spinal cord, so it can cause harm at any time during pregnancy. This is why you should not drink alcohol if you are pregnant.

Animal studies. Animal studies are the main way to find out if a medicine or other substance is safe during human pregnancy. Observations from human exposure.