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