2.2 Definitions:
Preeclampsia was defined as a new-onset persistent blood pressure (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg) and proteinuria (based on a 24-hour urine collection with a total protein excretion > 300 mg or a urinary spot measurement of protein-to-creatinine ratio > 0.3) after 20 weeks of gestation, according to the clinical guidelines established by the American College of Obstetricians and Gynecologists90. Preterm PE was defined as those cases of diagnosed PE that required delivery before 37 weeks of gestation. The non-PE group was defined as normotensive pregnant women with a normal pregnancy who did not develop serious obstetric disease and who delivered a healthy newborn at term. Periodontitis and its severity were defined according to the classifications established by the 2017 World Workshop116,117: (1) interdental clinical attachment level (CAL) detectable in ≥ 2 non-adjacent teeth or (2) buccal or oral CAL ≥ 3 mm with pocketing > 3 mm detectable in ≥ 2 teeth. Gingivitis was defined in subjects who did not exhibit a periodontal probing depth (PPD) ≥ 3 mm, who were without CAL, and who had positive bleeding upon probing (BOP) in ≥ 10% of probe sites. Gingival health was defined as < 10% BOP sites, with a PPD ≤ 3 mm116–118.