To the Editor.— Since propoxyphene is the most commonly prescribed drug in the United States, it is of interest to know whether it might be associated with congenital malformations when given during pregnancy. The following case points out the pitfalls in attempting to establish such an association. A 35-year-old married woman had a premature but normal baby boy at age 21 years, another normal child at age 23 years, and three spontaneous abortions over a seven-year period. At age 32 years, she began taking propoxyphene for chronic abdominal pain and a variety of emotional problems. From 20 to 36 capsules (65 mg each) were consumed daily and the patient also began noting peculiar "seizures" after withholding the medication for 12 to 18 hours. She therefore assumed she was addicted. At age 33 years, she became pregnant, developed much nausea and vomiting, and gained 50 lb. In addition to her usual