When is the immunity weakest during menstruation?

The third day. According to the query of 39 Health Network, during menstruation, the change of hormone level in women will lead to the decline of immunity. On the third day, because the hormone level in the body changes greatly, it is prone to abdominal pain, backache, fatigue and other discomfort symptoms, and at this time, the menstrual flow is relatively large, which will also lead to the decline of the body's immunity and easily induce diseases such as colds, so the immunity on the third day of menstruation is the weakest.