Documentation of contraception and pregnancy when prescribing potentially teratogenic medications for reproductive-age women

Teratogen: Any agent that can disturb the development of an embryo or fetus. Teratogens may cause a birth defect in the child. Or a teratogen may halt the pregnancy outright. The classes of teratogens include radiation, maternal infections, chemicals, and drugs.

Schwarz EBPostlethwaite DAHung YYArmstrong MA
Center for Research on Health Care, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. schwarzeb@upmc.edu

BACKGROUND: Certain medications are identified by the U.S. Food and Drug Administration (FDA) as class D or X because they increase the risk for birth defects if used during pregnancy. OBJECTIVE: To assess pregnancy rates and the frequency of contraceptive counseling documented with prescriptions for class D or X drugs filled by women of reproductive age. DESIGN: Description of prescriptions filled in 2001. SETTING: A large health maintenance organization in northern California in 2001. PATIENTS: 488,175 women age 15 to 44 years who filled a total of 1,011,658 class A, B, D, or X prescriptions. MEASUREMENTS: Medications dispensed, contraceptive counseling, and pregnancy testing. RESULTS: A class D or X prescription was filled by 1 of every 6 women studied. Women who filled a prescription for class D or X medications were no more likely than women who filled prescriptions for safer, class A or B medications to have received contraceptive counseling, filled a contraceptive prescription, or been sterilized (48% vs. 51% of prescriptions). There was little variation by clinical indication in rates of contraceptive counseling with class D or X prescriptions, except for isotretinoin. Women who filled a class D or X prescription were only slightly less likely to have a pregnancy documented within 3 months than women filling a class A or B prescription (1.0% vs. 1.4% of prescriptions). LIMITATIONS: International Classification of Diseases, Ninth Revision, codes underestimate contraceptive counseling. Documentation of a positive pregnancy test after filling a prescription may overestimate medication use in early pregnancy. Women who filled several prescriptions are overrepresented in prescription analyses.
CONCLUSION: Prescriptions for potentially teratogenic medications are frequently filled by women of childbearing age without documentation of contraceptive counseling.
United States FDA Pharmaceutical Pregnancy Categories
Pregnancy Category A Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).
Pregnancy Category B Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women OR Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in any trimester.
Pregnancy Category C Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Pregnancy Category D There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Pregnancy Category X Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.
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Author: Leslie Carol Botha

Author, publisher, radio talk show host and internationally recognized expert on women's hormone cycles. Social/political activist on Gardasil the HPV vaccine for adolescent girls. Co-author of "Understanding Your Mood, Mind and Hormone Cycle." Honorary advisory board member for the Foundation for the Study of Cycles and member of the Society for Menstrual Cycle Research.