There can be many causes of inter-menstrual bleeding.It could be due to the hormonal reasons, due to any polyp or growth arising from inside the uterus or from the cervix. It needs to be investigated properly to find out the cause.
Next Steps
Get the
thyroid test done, get an ultrasound pelvis done. Also the Pap smear test should be done to rule out any changes in the cervix. Once the cause is found it can be treated accordingly.