The aims of this study were to evaluate the possible associations between stress and pregnancy through scanning for gingivitis and to explore the effect of non-surgical periodontal therapy (NPT) on stress-related markers (CgA, AA, β-endorphin, DHEA, sIgA and NPY) and sex steroid levels (estrogen and progesterone) in pregnant and non-pregnant women. This evidence concerns the gene NPY and gingivitis.