Hello,
thanks for using health care magic,

Bleeding between periods is medically called metrorrhagia. It is a common symptom in women which could indicate normal as well as severe conditions.

Causes are numerous and could include:
-uterine fibroids
-Dysfunctional uterine bleeding
-Endometriosis
-Hormonal imbalance
-Polyps
-Infections such as Endometritis, Cervicitis and Vaginitis.

It would be better to consult your local doctor for detail evaluation and appropriate investigations

You could get back to me for more clarifications at http://www.healthcaremagic.com/doctors/dr-achuo-ascensius/64912

Best regards
Dr Achuo

Hello and welcome to HCM.

Thank you for your query.

I understand your concern. Let me try to help by listing some of the most common causes for such a bleed, between menstrual periods, taking into consideration your history (age, no medications and not sexually active). The possibilities are:
-Thyroid abnormalities (especially hypothyroidism)
-Ovarian cysts
-Vaginal infections
-Fibroids
-Polyps
-Endometriosis
-Dysfunctional uterine bleeding (DUB)
-Cervical cancer (rare and least likely)
and a few others. Although, I personally feel the above listed causes are the most likely ones. Please consult your doctor at the earliest for an ultrasound examination and blood investigations to rule out/diagnose the problem. Wishing you lots of luck.

I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications at: http://doctor.healthcaremagic.com/doctors/dr-shoaib-khan/64581 . I would gladly help you.

Best wishes.