Teratogenesis: A Review of the Basic Principles with a Discussion of Selected Agents: Part III

Abstract

Before a woman realizes she is pregnant, a large amount of development has occurred in the embryo. If she consumes a drug during her pregnancy, the possibility exists that the drug could harm the fetus. The most important variable is timing, with the fetus showing the highest degree of susceptibility during the first trimester of gestation. This article presents data on the relative time a pregnancy test becomes positive as compared to fetal development; passage of drugs across the placenta; placental and fetal drug metabolism; and the availability of teratogenic information to health professionals. Teratogenic effects of specific substances or classes of substances are discussed, including alcohol, analgesics, antibiotics, anticoagulants, anticonvulsants, antithyroid/thyroid drugs, various environmental agents, and paternal drug exposure.

Selecting Drugs for the Pregnant Dental Patient

“…For some congenital defects, such as cleft lip with or without cleft palate, there are many possible causes, which complicates the assessment of added risk for any specific drug. 9 The teratogenic potential for some drugs may be dependent on a genetic predisposition involved in fetal development. 10 For many drugs that are new or infrequently prescribed, accurate assessment of human risk is impossible.…”

“…7,11,12 Aspirin should be avoided-particularly late in pregnancy-because it is associated with delivery complications and postpartum hemorrhage in the mother. 13 Chronic use of aspirin early in the pregnancy has been associated with anemia in pregnant women.…”

“…Therefore, aspirin and any of the other NSAIDs should be avoided, particularly during the third trimester of pregnancy. 13 The synthetic prostaglandin analog misoprostol (Cytotec, G.D.…”

“…Chloramphenicol is contraindicated in pregnancy because of maternal toxicity and fetal circulatory failure, called gray syndrome. 10,13,16 Sedatives/anxiolytics. Administration of any of the central nervous system depressants commonly used for sedation is problematic.…”

“…Delivery complications and birth defects are more commonly caused by the mother's poor nutrition, smoking, alcohol consumption, disease, genetic predisposition and age. 10,30 Maintaining a healthy lifestyle, including optimal oral health, is essential for women who are currently pregnant or who are planning to become pregnant. For example, recent evidence has implicated periodontal infections as a possible factor associated with the delivery of low-birth-weight babies.…”