RESUMO
INTRODUCTION: Food insecurity represents a public health issue that has been associated with poor birth outcomes. We describe the methodological steps followed to structure and validate a questionnaire, which has the potential to contribute to the planning and conduction of future studies investigating the possible association between maternal food insecurity and fetal structural anomalies. METHODS: We first conducted a literature review to structure and validate the questionnaire. Subsequently, we drafted the questionnaire based on the results of this review, further refined through two focus groups. Afterward, the questionnaire was submitted using the Delphi Method to a panel of experts for validation. We conducted a pilot study prior to recruiting the final sample. RESULTS: The questionnaire consisted of sections covering information about socio-demographic characteristics, women's health and lifestyle, pregnancy, and food security status. After the first Delphi round, the Content Validity Index (CVI) for each section ranged 0.81-0.85, while after the second round all items had a CVI of 1. The final version of the questionnaire, consisting of 87 items, was pilot tested among 20 participants. Cronbach's Alpha for each section resulted in values higher than 0.6. The response rate ranged from 78 to 100%. A situation of food security was present in 85% of the participants, while 5% were in a situation of mild food insecurity and 10% of moderate food insecurity. CONCLUSION: The questionnaire has appropriate measurement properties, and is an adequate instrument to evaluate the association between maternal food insecurity and fetal structural anomalies.