Nearly 4 percent of pregnant women in the United States take illicit drugs during pregnancy, the March of Dimes says, and even more are addicted to legal but potentially harmful drugs such as alcohol and nicotine. Most drugs easily cross the placenta and reach the growing fetus. Both illegal and legal drug use in pregnancy can cause serious problems for the fetus during pregnancy and after delivery. The fetus can be at risk for birth defects and preterm delivery. It can also be born with addictions and experience drug withdrawal after delivery.
Marijuana
Marijuana is the illegal drug most commonly used in pregnancy. Fetal effects are seen most often in women who smoke marijuana six or more times a week. Regular marijuana use is associated with low birth weight and premature delivery. After delivery, some babies have withdrawal symptoms, including tremors, temperature instability, poor sleep patterns and irritability.
Stimulants
Stimulants such as Ecstasy, amphetamines and methamphetamines can have serious effects on a fetus. Intrauterine growth retardation and small head size may occur. Cleft palate and heart defects are noted as fetal risks from methamphetamines. Ecstasy may increase the risk of clubfoot in baby girls. Women who used methamphetamines were three times more likely to have low birth weight infants, according to a study reported by the March of Dimes.
Cocaine
Cocaine use can cause intestinal abnormalities, placental abruption, preterm labor, fetal hypertension or miscarriage. Cocaine use is also associated with an increased risk of sudden infant death, or SIDS, according to the Lucile Packard Children's Hospital at Stanford. Fetal hypertension can result in stroke. Urinary tract deformities may also be a result of cocaine addiction.
Opioids
Opioids such as heroin are associated with low birth weight in as many of half of cases. Heroin addiction may also cause premature rupture of membranes, preterm delivery, respiratory difficulties at birth, and neonatal abstinence syndrome, or NAS. NAS causes withdrawal symptoms of irritability, poor feeding, jittery feelings, diarrhea, vomiting and seizures. Affected infants are treated with medications, often for weeks, so they can withdraw slowly and safely. Mothers who stop heroin use abruptly in pregnancy have a higher risk of miscarriage or stillbirth.
Alcohol
Alcohol use in pregnancy can be devastating to the fetus, resulting in fetal alcohol syndrome, or FAS, which causes not only distinct facial features but mental retardation and behavioral disorders. The Merck Manual indicates that as few as three drinks a day can cause FAS. Even drinking a lesser amount daily doubles the risk of miscarriage.
Nicotine
Nicotine is a legal drug, but maternal addiction can still have negative effects on the fetus. Merck states that only 20 percent of smokers quit during pregnancy. Smokers have an increased risk of miscarriage, stillbirth, preterm delivery and low birth weight. Placental problems such as abruption and placenta previa, where the placenta covers all or part of the cervix making vaginal delivery impossible, also occur more frequently in smokers.
