I noticed last month right after I ovulated my gums were swollen and this month they are also. I googled and found this.
Before Menstruation. Gingivitis may flare up in some women a few days before they menstruate, when progesterone levels are high.
Gum inflammation may also occur during ovulation. Progesterone dilates blood vessels causing inflammation, and blocks the repair of collagen, the structural protein that supports the gums
http://adam.about.com/reports/Periodontal-disease.htm
Maybe I did O on CD 12