Background The use of oral complementary and alternative medicines, including herbal supplements, has been increasing in pregnant women worldwide despite limited safety data. The decision of healthcare professionals to recommend these products to pregnant patients is controversial and not well documented. Objective To explore the recommendations and information sources that healthcare professionals use to determine the safety of oral non-prescribed supplements during pregnancy. Setting An Australian metropolitan maternity hospital. Method An electronic survey was distributed to doctors, midwives, pharmacists, dietitians, lactation consultants and physiotherapists. Main outcome measure The nature of recommendations and information sources that healthcare professionals use to determine the safety of oral non-prescribed supplements during pregnancy. Results Responses were received from 54 healthcare professionals. Forty of 54 (74.1%) were concerned about the safety of their patients' supplements, while 35 of 54 (64.8%) felt that they had access to trustworthy safety information. Supplements most commonly recommended as safe to use were ginger (40.7%), probiotics (29.6%) and raspberry leaf (22.2%). Participants specifically requested further safety information for raspberry leaf, evening primrose oil, fish oil, probiotics, ginger, vitamin C, valerian, turmeric, blue cohosh and colloidal silver. Written resources most frequently consulted included MIMS (61.1%) and 'Google Searches' (29.6%), and healthcare professionals most referred to were pharmacists (74.1%), doctors (22.2%), and naturopaths or herbalists (3.7%). Conclusion The recommendations of maternity heath care professionals and quality of information sources used varied. Further education and access to unbiased safety information is required to empower healthcare professionals to provide informed recommendations to pregnant patients.