Introduction: Gingivitis is a condition that has been associated with an exaggerated inflammatory response of the gums to oral biofilm, attributed to the secretion of hormones during pregnancy. Objectives: To estimate the prevalence of gingivitis and identify associated risk factors among pregnant women in a medical clinic from Acapulco, Guerrero. Material and methods: Cross-sectional study in a convenience sample of 92 pregnant women, during the period from January to March 2020. A self-administered questionnaire collected sociodemographic data, economic income, oral hygiene habits and personal pathological history. The periodontium was evaluated based on the new classification of gingival health and gingivitis induced by oral biofilm on six representative teeth. Multivariate analysis identified factors associated with gingivitis using the odds ratio and its 95% confidence interval as a...