Monitoring pregnancy outcomes after prenatal drug exposure through prospective pregnancy registries: A pharmaceutical company commitment

OBJECTIVE: Glaxo Wellcome becomes aware of prenatal exposures to its medica tions as early as the clinical trial phase of development. An international process for monitoring prenatal exposure to all Glare Wellcome medicines h as been developed. For specific products there are prospective pregnancy re gistries. STUDY DESIGN: The registries are observational, case-registration, and foll ow-up studies designed to detect evidence of teratogenicity associated with specific medications. After prenatal exposure to the registry medication, pregnancies are registered prospectively, through voluntary reports by heal th care providers. An advisory committee of independent scientists for each registry reviews data and advises in dissemination or information. Risk of birth defects, as defined by the Centers for Disease Control and Preventio n, is compared with published risks both in women in the general population and in women with the underlying condition being treated, if available. RESULTS: The following data show results from the prospective first-trimest er exposures registered since establishment of each registry. The published risk of birth defects in the general population range is 3% to 5%, and the risk in women with epilepsy is 6% to 9%. The proportions of outcomes with birth defects are as follows: in the Acyclovir (antiviral medication) Pregn ancy Registry (1984-1998) (19/581), 3.3% (95% confidence interval, 2.0%-5.2 %); in the Lamotrigine (monotherapy and polytherapy antiepileptic medicatio n) Pregnancy Registry (1992-September 1998) (8/123), 6.5% (95% confidence i nterval, 3.1%-12.8%); in the Sumatriptan (migraine medication) Pregnancy Re gistry (1996-October 1998) (7/183), 3.8% (95% confidence interval, 1.7%-8.0 %). The Valacyclovir, Bupropion, and Naratriptan registries have insufficie nt data for analysis. CONCLUSION: None of the registries has provided a risk estimate exceeding t hat expected in the disorder treated, and no pattern of defects has been ob served. Whereas information from the larger registries is reassuring regard ing risk, these studies cannot rule out possible small excess risks from us e of these drugs in pregnancy. Data obtained through these registries are s hared with the medical community as a supplement to animal toxicology studi es to assist in weighing potential risks and benefits of treatment for indi vidual patients. The success of the registries depends on the continued wil lingness of the obstetrics and gynecology community to notify the registrie s of prenatal exposures.