NIH Study Shows COVID Shot Affects Menstrual Cycle

Menstrual cycles were longer by about a day when women received COVID-19 shots. When two doses were received in one cycle, the changes became more severe, in some cases changing by eight days or more.

STORY AT-A-GLANCE

• A study in Obstetrics & Gynecology found that those who received COVID-19 shots had longer menstrual cycles, typically by less than one day, when they received the shots

• The longer cycles were noted for both doses of the injection, with a 0.71-day increase after the first dose and 0.91-day increase after the second dose

• Some women experie…