This report is an extension of the study by Wilson and associates1on the teratogenic effects of Asian influenza. The original report included only 126 of the 738 pregnancies with serological data regarding Asian influenza. Since the results of our early report and other investigations1-7have not been conclusive regarding the teratogenic effects of Asian influenza, we decided to search for the medical records of the pregnancies in our original cohort which had not been examined. Our original cohort represented a large number of patients with serological evidence of influenza infection. Few studies have had such substantiating serological data.5,7Other studies have used primarily medical history for evidence of influenza in the mothers, which is not completely satisfactory. In fact, our data showed that history of influenza and serological titer in the mothers were not correlated. Sixty percent of the mothers who denied having had influenza were