In embryonic period, causes blindness and deafness; in first and
second trimesters, causes brain damage.
Preventive measures:
Immunization before becoming pregnant.
Toxoplasmosis
Effects of exposure on fetus:
Brain damage, loss of vision, intellectual disabilities.
Preventive measures:
Avoid eating undercooked meat and handling cat feces, garden dirt during pregnancy.
Measles, chicken pox, influenza
Effects of exposure on fetus:
May impair brain functioning.
Preventive measures:
Immunization of all children and adults.
Syphilis
Effects of exposure on fetus:
Baby is born with syphilis, which, untreated, leads to brain and
bone damage and eventual death.
Preventive measures:
Early prenatal diagnosis and treatment with antibiotics.
HIV
Effects of exposure on fetus:
Virus may be transmitted to baby. Without treatment, illness and death are
likely during childhood.
Preventive measures:
Prenatal drugs and cesarean birth make HIV transmission rare.
Other STIs, including gonorrhea and chlamydia
Effects of exposure on fetus:
Not usually harmful during pregnancy but may cause blindness and
infections if transmitted during birth.
Preventive measures:
Early diagnosis and treatment; if necessary, cesarean section, treatment of newborn.
Infections, including infections of urinary tract, gums, and teeth
Effects of exposure on fetus:
May cause premature labor, which increases vulnerability to brain
damage.
Preventive measures:
Good, inexpensive medical care before pregnancy.
Pollutants
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Lead, mercury, PCBs (polychlorinated
biphenyls); dioxin; and some pesticides, herbicides, and cleaning compounds
Effects of exposure on fetus:
May cause spontaneous abortion, preterm labor, and brain
damage.
Preventive measures:
May be harmless in small doses, but pregnant women should avoid exposure, such as drinking well water,
eating unwashed fruits or vegetables, using chemicals, eating fish from polluted waters.
Radiation
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Massive or repeated exposure to
radiation, as in medical x-rays
Effects of exposure on fetus:
May cause small brains (microcephaly) and intellectual
disabilities. Background radiation probably harmless.
Preventive measures:
Sonograms, not X-rays, during pregnancy. Pregnant women who work directly with radiation need special
protection.
Social and Behavioral Factors
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Very high stress
Effects of exposure on fetus:
May cause cleft lip or cleft palate, spontaneous abortion, or
preterm labor.
Preventive measures:
Adequate relaxation, rest, and sleep; reduce intensity of employment and seek help from spouse, family members, or your doctor if you face severe stress.
Malnutrition
Effects of exposure on fetus:
When severe, interferes with conception, implantation, normal
fetal development.
Preventive measures:
Eat a balanced diet, normal weight before pregnancy, gain 25–35 lbs (10–15 kg) during pregnancy.
Excessive, exhausting exercise
Effects of exposure on fetus:
Can harm fetal growth if it interferes with woman’s sleep,
digestion, or nutrition.
Preventive measures:
Regular, moderate exercise is healthy. Can harm fetal growth if it interferes with woman’s sleep, digestion, or nutrition.
Medicinal Drugs
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Lithium
Effects of exposure on fetus:
Can cause heart abnormalities.
Preventive measures:
Avoid all medicines, whether prescription or over-the-counter, during pregnancy unless given by a
medical professional who knows recent research on teratogens.
Tetracycline
Effects of exposure on fetus:
Can harm teeth
Preventive measures:
Avoid all medicines, whether prescription or over-the-counter, during pregnancy unless given by a
medical professional who knows recent research on teratogens.
Retinoic acid
Effects of exposure on fetus:
Can cause limb deformities.
Preventive measures:
Avoid all medicines, whether prescription or over-the-counter, during pregnancy unless given by a medical professional who knows recent research on teratogens.
Streptomycin
Effects of exposure on fetus:
Can cause deafness
Preventive measures:
Avoid all medicines, whether prescription or over-the-counter, during pregnancy unless given by a medical professional who knows recent research on teratogens.
ACE inhibitors
Effects of exposure on fetus:
Can harm digestive organs.
Preventive measures:
Avoid all medicines, whether prescription or over-the-counter, during pregnancy unless given by a medical professional who knows recent research on teratogens.
Phenobarbital
Effects of exposure on fetus:
Can affect brain development.
Preventive measures:
Avoid all medicines, whether prescription or over-the-counter, during pregnancy unless given by a medical professional who knows recent research on teratogens.
Thalidomide
Effects of exposure on fetus:
Can stop ear and limb formation.
Preventive measures:
Avoid all medicines, whether prescription or over-the-counter, during pregnancy unless given by a medical professional who knows recent research on teratogens.
Psychoactive Drugs
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Caffeine
Effects of exposure on fetus:
Normal, modest use poses no problem.
Preventive measures:
Avoid excessive use. (Note that coffee, tea, cola drinks, chocolate all contain caffeine.)
Alcohol
Effects of exposure on fetus:
May cause fetal alcohol syndrome (FAS) or fetal alcohol effects
(FAE).
Preventive measures:
Stop or severely limit alcohol consumption; especially dangerous are three or more drinks a day or four or more drinks on one occasion.
Tobacco
Effects of exposure on fetus:
Reduces birthweight, increases risk of malformations of limbs and
urinary tract, and may affect the baby’s lungs.
Preventive measures:
Ideally, stop smoking before pregnancy. Stopping during pregnancy also beneficial.
Marijuana
Effects of exposure on fetus:
Heavy exposure affects central nervous system; when smoked, may
hinder fetal growth.
Preventive measures:
Avoid or strictly limit marijuana consumption
Heroin
Effects of exposure on fetus:
Slows fetal growth, increases prematurity. Addicted newborns need
treatment to control withdrawal.
Preventive measures:
Treatment needed before pregnancy but if already pregnant, gradual withdrawal on methadone is better than continued use of heroin.
Cocaine
Effects of exposure on fetus:
Slows fetal growth, increases prematurity and then learning
problems.
Preventive measures:
Stop before pregnancy; if not, babies need special medical and educational attention in their early
years.
Inhaled solvents (glue or aerosol)
Effects of exposure on fetus:
May cause abnormally small head, crossed eyes, and other
indications of brain damage.
Preventive measures:
Stop before becoming pregnant; damage can occur before a woman knows she is pregnant.
*The field of toxicology advances daily. Research on new substances begins with their effects on nonhuman species, which provides suggestive (though not conclusive) evidence. This activity is a primer; it is no substitute for careful consultation with a knowledgeable professional.