Effects of Drugs During Pregnancy

A teratogen is any substance that can produce birth defects in a developing baby. Drugs, both legal and illegal, fit under this classification if they harm the fetus. The use of prescription and nonprescription drugs is high. Approximately 40-60% of women use one drug during pregnancy. However, 2% of birth defects are caused by drugs consumed by the mother. Even though the amount of birth defects caused by drugs are low, it is very important for women to know what drugs have the potential to harm their child. Before stopping any medication, it is very important to seek the advice of a medical professional.

Cigarette Smoking

Cigarette smoking is greatly known to cause intrauterine growth retardation to a developing baby. Smoking while pregnant may also cause urinary tract abnormalities, behavioral problems, and decreased growth. Nicotine, a component to tobacco in cigarettes, constricts uterine blood vessels which causes less blood flow to the fetus. This impairs cell growth and decreases mental development. Cigarette smoking also causes high levels of carboxyhemoglobin in the blood. The mother is unable to transport oxygen to the fetus, which may cause chronic fetal hypoxia (oxygen deprivation). This would result in decreased rate of fetal growth and development.

Alcohol

Moderate to high levels of alcohol consumption during pregnancy may cause birth defects. Fetal Alcohol Syndrome, a pattern of birth defects seen in newborns whose mothers consumed high amounts of alcohol, occurs in 2/1000 live births. These birth defects include growth deficiencies, microcephaly (small head), face abnormalities, and joint abnormalities. Alcohol abuse during pregnancy is thought to be the most common cause of mental retardation. Moderate alcohol consumption during pregnancy may cause a pattern of behavioral and learning defects called Fetal Alcohol Effects (FAE). It is best for women to abstain from alcohol throughout their whole pregnancy.

Androgens/Progestogens

Progestin
Progestin consumption during pregnancy may cause cardiovascular abnormalities. Males are also twice as likely to have urogenital abnormalities.

Testosterone
Testosterone consumption during pregnancy may cause masculization of the female fetus.

Birth Control
Using progestogen-estrogen birth control pills in the early stages of pregnancy is known to cause VACTERL syndrome. VACTERL stands for vertebral, anal, cardiac, trachea, esophageal, renal, and limb abnormalities. Birth control should be stopped as soon as pregnancy is detected.

Diethylstilbestrol (DES)
Diethylstilbestrol is known to cause uterine abnormalities and vaginal abnormalities in female fetuses exposed in utero. DES is also known to cause genital tract abnormalities in the male fetus.

Antibiotics

Tetracyclins
Tetracyclins consumed during pregnancy may cause yellow staining of the primary and secondary teeth and may also cause tooth defects.

Streptomyocin Derivatives
Streptomyocin derivatives consumed during pregnancy may cause deficiencies in hearing and 8th cranial nerve damage.

Penicillin
Penicillin consumed during pregnancy does not harm the fetus.

Anticoagulants

Warfin
Warfin is used for treatment of thromboembolitic disease and is also used with patients with artificial heart valves. Warfin consumed during pregnancy may cause facial defects, central nervous system abnormalities, mental retardation, eye defects, and microcephaly (small head).

Heparin
Heparin is not a teratogen and is safe during pregnancy.

Anticonvulsants

Trimethadione (Tridione)
Consumption of trimethadione during pregnancy may cause a pattern of birth defects called fetal trimethadione syndrome. These abnormalities include growth retardation, face defects, heart defects, urogenital defects, and limb defects.

Phenytoin (Dilantin/Novophenytoin)
Consumption of phenytoin during pregnancy may cause a pattern of birth defects called fetal hydantoin syndrome. This syndrome happens in approximately 5-10% of children whose mothers took phenytoin. These abnormalities include intrauterine growth retardation, microcephaly, mental retardation, and facial abnormalities.

Valporic Acid
Valporic acid consumed during pregnancy may cause craniofacial defects, heart defects, limb defects, and neural tube defects.

Phenobarbitol
Phenobarbitol is safe to consume during pregnancy.

Isothretinion

Isothretinion is used to treat acne and is highly harmful to the fetus if used during pregnancy. Using Isothretinoin during pregnancy may result in spontaneous abortion of the fetus, facial defects, heart abnormalities, neural tube defects, and neuropsychological impairment.

Thyroid Drugs

Potassium iodide/radioactive iodide
Using potassium iodide and high amounts of radioactive iodide during pregnancy can result in a congenital goiter.

Iodides
Iodides may cause thyroid enlargement and cretinism if consumed during pregnancy.

Propylthiouracil
Propylthiouracil effects thyroxin formation of the fetus. Consumption during pregnancy may cause a goiter.

Tranquilizers

Thalidomide
Thalidomide has been well-known to cause limb defects if consumed during pregnancy. Other birth defects include ear deformities, heart defects, urinary tract defects, and GI tract defects.

Lithium

Lithium is used with the treatment of bipolar disorder. If taken during pregnancy, it may result in defects of the heart and great vessels. The patient and doctor usually discuss the risks and benefits before taking a patient off Lithium during pregnancy.

Illicit Drugs

Lysergic Acid Diethylamide (LSD)
Abusing LSD during pregnancy may result in nervous system abnormalities.

Cocaine
Abusing cocaine during pregnancy may result in spontaneous abortion, prematurity, intrauterine growth retardation, microcephaly, urogenital abnormalities, and behavioral disturbances.

Works Cited
Moore, Keith, and T.V.N. Persaud. The Developing Human Clinically Oriented Embryology. Philadelphia: Saunders, 2003.