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Teratogens

Infectious Diseases

Rubella (German Measles) If a pregnant woman contracts rubella during the embryonic stage, the consequence is, not infrequently, mental retardation, blindness, or eye, ear, and heart abnormalities in the baby- depending on the week the virus enters the blood stream. Luckily, women of childbearing age are now routinely immunized for this otherwise minor adult disease.

Cytomegalovirus About 25% of babies infected with this virus develop vision or hearing loss; 10% develop neurological problems.

AIDS HIV-Infected women can transmit the virus to their babies prenatally through the [placenta, during delivery (when blood is exchanged between the mother and the child), or after birth (through the breast milk). Rates of transmission are much lower if infected mothers take the anti-Aids drug AZT or if newborns are given a new drug that blocks the transmission of HIV at birth. If a mother takes these precautions, does not breast feed, and delivers her baby by C-Section, the infection rate falls to less than 1%. While mother to child transmission of HIV has declined dramatically in the developed world, it remains a devastating problem in sub-Saharan Africa and other impoverished regions of the globe (Avert, 2005).

Herpes This familiar sexually transmitted disease can cause miscarriage, growth retardation, and eye abnormalities in affected fetuses. Doctors recommend that pregnant women with active genital herpes undergo C-sections to avoid infecting their babies during delivery.

Toxoplasmosis This disease, caused by a parasite found in raw meat and cat feces, can lead to blindness, deafness, and mental retardation in infants. Pregnant women should avoid handling raw meat and cat litter.

Medications

Antibiotics Streptomycin has been linked to hearing loss; tetracycline to stained infant tooth enamel

Thalidomide This drug prescribed in the late 1950s in Europe and Americas to prevent nausea during the first trimester, prevented the baby’s arms and legs from developing if taken during the embryonic period.

Anti-seizure drugs These medications have been linked to developmental delays during infancy

Anti-psychotic drugs These drugs may slightly raise the risk of giving birth to a baby with heart problems.

Antidepressants Although typically safe, third-trimester exposure to selective serotonin reuptake inhibitors and tricyclic anti-depressants has been linked to temporary jitteriness and excessive crying and to eating and sleeping difficulties in newborns. Rarely, these drugs can produce a serious syndrome involving seizures and dehydration, as well as higher rates of “miscarriage.”

Recreational Drugs

Cocaine This drug is linked to miscarriage, growth retardation, and learning and behavior problems.

Methamphetamines This drug may cause miscarriage and growth retardation.

Environmental Toxins

Radiation Japanese children exposed to radiation from the atomic bomb during the second trimester had extremely high rates of severe mental retardation. Miscarriages were virtually universal among pregnant women living within 5 miles of the blast. Pregnant women are also advised to avoid clinical doses of radiation such as those used in x-rays (and especially cancer treatment radiation).

Lead Babies with high levels of lead in the umbilical cord may show impairments in cognitive functioning (Bellinger and others, 1987). Maternal and paternal exposure to lead is associated with miscarriage.

Mercury and PCBs These pollutants are linked to learning and behavior problems.

Stress A vast array of studies suggest severe stress during pregnancy is linked to miscarriage, premature delivery, and learning and behavior problems- as well as possibly having long-term effects on adult health (see page 54 of text). But moderate stress during the second and third trimesters may accelerate prenatal growth and so promote better health at birth.

Vitamin Deficiencies In addition to eating a balanced diet, every women of childbearing age should take folic acid supplements. This vitamin, part of B complex, protects against the incomplete closure of the neural tube during the first month of development- an event that may produce spina bifida (paralysis in the body below the region of the spine that has not completely closed) or anencephaly (failure of the brain to develop-and certain death) if the gap occurs toward the top of the developing neural tube.

General sources: Huttenlocher, 2002, and the references in this chapter. Sources specifically correlating Stress with child problems: Bergman

and others, 2010; Bregnab and others, 2010; Buss and others, 2010; Charil, and others, 2010; Douglas, 2010; Figueiredo and others, 2010;

Rice and others, 2010; and Schetter, 2011.