What causes the woman to menstruate twice in the same month?

What causes the woman to menstruate twice in the same month? On the 1st day I was menstruated and I took my injection on the 8th day, but yesterday it came again, now with little flow. This is not the first time this happens to me, it must be the fourth one ... the question that also follows is: should I take the injection again?
Expert answer:

The woman can menstruate twice in the same month when she has a short menstrual cycle. Thus, the interval between one menstruation and another is less than 28 days and occasionally it may coincide of the two menses occurring in the same month.

Menstruating twice in the same month is not necessarily a sign of trouble or illness. Contraceptives, hormonal changes and stress are the main causes.

Some factors can cause menstruation to go down twice in the same month are:

  • Stress and emotional changes;
  • Fibroids, cancer, polycystic ovaries, ovarian cyst;
  • Use of medications such as birth control;
  • Hormonal and emotional changes;
  • Ovarian surgery;
  • Ligation.

The use of injectable contraceptives may lead to escape bleeds throughout the menstrual cycle. Even so, the woman should continue normal use of the medication and should take the injection on the scheduled date.

If you menstruate twice a month often, consult your family doctor, general practitioner or gynecologist for evaluation of your health status, as well as consider a possible contraceptive change if such bleeding escape are causing discomfort.