Centers for Disease Control and Prevention
http://www.cdc.gov/pregnancy/meds (facts sheets for patients; link to LacMed, a database of medications that might be used during lactation)
Clinical Pharmacology
http://www.clinicalpharmacology.com (medication summaries, used by most pharmacies, membership required)
National Library of Medicine
http://dailymed.nlm.nih.gov/dailymed/about.cfm (information for physicians and patients; more current than U.S. Food and Drug Administration website)
Online Physicians' Desk Reference
http://www.pdr.net (medication reference for physicians, membership required)
Organization of Teratology Information Specialists
http://www.mothertobaby.org/fact-sheets-s13037 (fact sheets for patients)
Reproductive Toxicology Center
http://www.reprotox.org (medication summaries; membership required)
University of Toronto, The Hospital for Sick Children, Motherisk Program
http://www.motherisk.org/women/drugs.jsp (index of medications, including over-the-counter)
http://www.motherisk.org/women/mothernature.jsp (index of herbal products)
U.S. Food and Drug Administration
http://www.fda.gov/ForConsumers/ByAudience/ForWomen/WomensHealthTopics/ucm117976.htm#Medicine_and_Pregnancy (resources for patients)