It is difficult to examine the safety of drugs during pregnancy. This thesis examines the best strategy for the Motherisk Program to generate risk signals for drug use in pregnancy. Three studies were used to evaluate their strategy. A meta-analysis examining the safety of metformin during pregnancy, a systematic review examining the drugs used in the treatment of allergic rhinitis during pregnancy and a computerized database of calls from the Motherisk call centre, MotherNET, was created to aid in conducting prospective studies.Systematic reviews will serve some problems in conducting teratogenicity studies (ie. ethical concerns and small sample sizes). MotherNET will aid in reducing the time required to collect a patient cohort and in recruiting eligible candidates for studies. Systematic reviews together with MotherNET will allow the Motherisk Program to generate risk signals on drugs used during pregnancy.