The Affect of Teratogens on Fetal and Child Development

For a woman giving birth to a healthy baby after nine months of pregnancy is nothing short of a miracle. Many harmful substances are filtered out by the placenta, however some may still pass through to the fetus. From harmful environmental chemicals to maternal diseases, there are many factors that can negatively affect the development of the fetus. These factors are referred to as teratogens. Teratogens are any chemical, substance, or exposure that could possibly cause birth defects in a developing fetus (Greater Baltimore Medical Center, p. 1). Exposure to teratogens seems to result in malformations especially when it occurs during the fourth and tenth week of pregnancy (The Merck Manuals Online Medical Library, p. 17). Four teratogens that affect fetal and child development are toxoplasmosis, varicella, isotretinoin, and cocaine.

Toxoplasmosis is an infection that is brought on by exposure to a single-celled parasite called Toxoplasma gondi. Toxoplasma gondi works it's way into the human body most commonly through accidental ingestion. For example, if a person doesn't wash his or her hands and then touches their mouth after changing the cat litter box or after preparing raw pork (Center for Disease Control and Prevention, p. 2). This parasite finds its home in over 60 million Americans; only causing serious health problems in pregnant women and people with weakened immune systems (Center for Disease Control and Prevention, p. 1.). If a woman contracts toxoplasmosis in the first trimester, the risk that the fetus will also be infected is about 15 percent. The risk rises to about 30 percent if she is infected in the second trimester and to 60 percent in the third trimester. Somewhere between 1 and 10 in 10,000 babies in the United States contract the infection in utero each year (Linden, p. 4). Toxoplasmosis has very negatives affects on a developing fetus, although most of the symptoms do not appear until after birth. It has been known to cause low birth weight, premature birth, enlarged liver and spleen, visual defects, mental retardation and intercranial calcifications. Treatment is available and it greatly reduces the risk of there being harm to the fetus, although treatment is usually unnecessary if the infection was not contracted during pregnancy (Linden, p. 5). A pregnant woman can take antibiotics to lower the risk of the fetus becoming infected. If the newborn is born with infection, he/she can be treated with a combination of pyrimethamine, sulphadiazine and folinic acid administered for one year (Birthcare, p. 8).

Varicella, more commonly known as the chicken pox, is a benign viral infection that is contracted through respiratory droplets or skin contact. If contracted during pregnancy, however, it can have cause harm to the fetus. 25% of fetuses may actually contract the virus from their infected mothers and even fewer will develop birth defects as a result of the virus. The greatest risk for birth defects is when the mother develops chicken pox between 8 and 20 weeks of pregnancy. The risk for birth defects due to chicken pox infection in the first trimester of pregnancy is 0.5-1 percent. When chicken pox occurs between 13 and 20 weeks of pregnancy, the risk for birth defects appears to be 2 percent (Organization of Teratology Information Specialists, p. 7-9). The infection can cause a birth defect called varicella embryopathy. Varicella embryopathy appears as scars, eye problems, poor growth, underdeveloped limbs, small head size, and mental retardation. Death can also occur in 50% of cases that are contracted in late pregnancy (Organization of Teratology Information Specialists, p. 10). Varicella can be treated the antiviral drug acyclovir. If a baby is born with the virus, he/she should be treated with varicella-zoster immune globulin for the first 3 days of life. If he/she appears ill then he/she should be given a treatment of IV acyclovir, as well.

Isotretinoin is a drug used for the treatment of acne. A clear complexion is not worth the risks during pregnancy, however. Of 34 exposed women reported, 19 experienced spontaneous miscarriage, and 10 babies were born with congenital malformations now understood to be the fetal isotretinoin syndrome (Dolan, p.1). Children with the fetal isotretinoin syndrome often have facial asymmetry; serious external ear abnormalities, small jaws; flat depressed nasal bridge; and widely spaced eyes. Doctors and pharmacists take precautions with women that they prescribe this drug to, telling them to use two forms of birth control while on the medication and to perform monthly pregnancy tests. The best form of treatment is prevention and to stop taking the drug upon discovering pregnancy (Dolan, p. 4).

Cocaine is street drug that has negative affects on the fetus and later child development. Cocaine use during pregnancy is known to stunt fetal growth, and it puts the fetus at risk for placental abruption, uterine rupture, and congenital heart defects (Genetic Drift, p. 17). Children exposed to cocaine may exhibit behavioral and emotion difficulties, attention deficit, sleep and eating disorders, difficulty in language and verbal development, and slowed gross and fine motor skill development (Alberta Alcohol and Drug Abuse Commission, p. 21-24). It is difficult to develop a treatment plan for children exposed to cocaine prenatal development because many of them appear to be normal (National Institute on Drug Abuse, p. 3).

In closing, the birth of a healthy child should bring about a sense of thankfulness in families. The prenatal period is a sensitive time where many things can go wrong, in terms of fetal development, if the mother is exposed to teratogens. Some exposures to teratogens can have life long affects on a baby. Toxoplasmosis, varicella, isotretinoin, and cocaine are just an example of some of the dangers that teratogens can produce. Women should make all attempts avoid exposure so that they can give birth to a healthy baby.

References:

Alberta Alcohol and Drug Abuse Commission. (2004). "Effects Series: Cocaine". Retrieved December 14, 2006 from http://corp.aadac.com/for_women/the_basics_about_women/women_effects_cocaine.asp

Birthcare. (2006). "Neonatal Problems: Congenital Toxoplasmosis" Retrieved December 14, 2006 from http://www.mybirthcare.com/toxoplasmosis.asp

Center for Disease Control and Prevention. (2004). "Toxoplasmosis". Retrieved December 14, 2006 from http://www.cdc.gov/NCIDOD/dpd/parasites/toxoplasmosis/factsht_toxoplasmosis.htm#what

Dolan, Siobhan. (2004). "Isotretinoin and Pregnancy: A Continued Risk for Birth Defects". Retrieved December 14, 2006 from http://www.medscape.com/viewarticle/492119

Genetic Drift. (2000). "Substances of Abuse". Retrieved December 14, 2006 from http://mostgene.org/gd/gdvol12c.htm

Greater Baltimore Medical Center. (2006). "Teratogens". Retrieved December 14, 2006 from http://www.gbmc.org/genetics/harveygenetics/prenataldx/PatientInformation/teratogens.cfm

Linden, Ann. (2005). "Toxoplasmosis During Pregnancy". Retrieved December 14, 2006 from http://www.babycenter.com/refcap/pregnancy/pregcomplications/1461.html#1

National Institute on Drug Abuse. (2006). "Research Report Series: Cocaine Abuse and Addiction". Retrieved December 14, 2006 from http://www.nida.nih.gov/ResearchReports/Cocaine/cocaine4.html

Organization of Teratology Information Specialists. (2002). "Chicken Pox (Varicella) and the Vaccine and Pregnancy". Retrieved December 14, 2006 from http://www.otispregnancy.org/pdf/chickenpox.pdf

The Merck Manuals Online Medical Library. (2005). "Risk Factors". Retrieved December 14, 2006 http://www.merck.com/mmpe/sec18/ch262/ch262b.html