BACKGROUND: There is a lack of basic knowledge on the part of both clinicians and patients as to the indications for use and safety of herbs used during pregnancy and lactation. This is one article in a series that systematically reviews the evidence for herbs commonly used during pregnancy and lactation. OBJECTIVES: To systematically review the literature for evidence on the use, safety and pharmacology of cranberry, focusing on issues pertaining to pregnancy and lactation. METHODS: We searched 7 electronic databases and compiled data according to the grade of evidence found. RESULTS: There is no direct evidence of safety or harm to the mother or fetus as a result of consuming cranberry during pregnancy. Indirectly, there is good scientific evidence that cranberry may be of minimal risk, where a survey of 400 pregnant women did not uncover any adverse events when cranberry was regularly consumed. In lactation, the safety or harm of cranberry is unknown. CONCLUSIONS: Women experience urinary tract infections with greater frequency during pregnancy. Given the evidence to support the use of cranberry for urinary tract infections (UTIs) and its safety profile, cranberry supplementation as fruit or fruit juice may be a valuable therapeutic choice in the treatment of UTIs during pregnancy.