Bleeding that occurs anytime between two consecutive menstrual periods is considered abnormal and needs to be investigated. First and foremost, it should be confirmed whether the bleeding is from the vagina, the rectum or the urinary tract. Get an immediate examination done by a trained healthcare professional if you experience intermenstrual bleeding. Do not wait for the bleeding to stop or reduce in intensity before you seek help.

Some common causes of abnormal menstrual bleeding include:

Infections: The female genital organs such as the uterus, fallopian tubes or ovaries can develop pelvic inflammatory disease or sexually transmitted diseases due to infections, which may result in abnormal bleeding.
 
Use of an Intra Uterine Device (IUD): The use of an IUD for contraception may be associated with intermenstrual bleeding. Sometimes, this occurs and subsides by itself. In severe cases, where the bleeding does not stop spontaneously, your healthcare provider might remove the IUD and suggest another method of contraception.
 
Uterine fibroids: The occurrence of these, especially submucous fibroid (tumor), can often lead to heavy menstrual bleeding or intermenstrual bleeding.

Hormonal imbalance: This is sometimes associated with a condition called polycystic ovarian syndrome (PCOS) and causes abnormal bleeding.
 
Oral contraceptive pills: The use of these can cause bleeding in between menses if the dose is improper or the woman takes the pills irregularly.