Objetive: To evaluate the correlation between salivary biomarkers (the salivary antioxidant ability, salivary level of polyphenols, and other antioxidants) with plaque-induced gingivitis exacerbated by pregnancy in pregnant and nonpregnant women. Material and Methods: For this observational study, medical records, dental examinations, and analyses of saliva samples were carried out in pregnant and nonpregnant women. A p-value of <0.05 was considered significant. Results: The pregnant women (n =17) exhibited a lower antioxidant capacity (p-value=0.0041), higher levels of polyphenols, gingival index, bleeding on probing, and subjects consuming mineral-enriched products (p-value from <0.0001 to 0.0466), and unchanged levels of phosphotungstic acid reactive substances, proteins, oral hygienic habits, plaque index and probing depth (p-value from 0.0683 to 0.8358), in comparison with the nonpregnant women (n=9). Also, a positive correlation between the gingival index and salivary polyphenol content was observed (r-value = 0.4087, p-value = 0.0202). Conclusion: The salivary polyphenols correlate with plaque-induced gingivitis exacerbated by pregnancy, suggesting a deficiency of salivary antioxidant protection.