Intermenstrual bleeding (IMB) – also called spotting, abnormal vaginal bleeding, or metrorrhagia – is bleeding that happens in between your periods; the average menstrual cycle is 28 days, although it can vary from 21 to 35 days. IMB should not be confused with irregular periods, which is when the period comes infrequently or at unpredictable times: shorter than 21 days or longer than 35 days.
IMB is very common and most women will experience it at some point in their lives. It has many possible causes – some harmless, some serious. Many young women, for instance, have intermenstrual or irregular bleeding, which is quite normal, until their cycle regulates. Still, it’s important not to ignore this symptom – no matter what your age – so see your doctor for a diagnosis and treatment.
Potential causes of Intermenstrual bleeding IMB include:
1. Hormonal imbalance – The hormones, estrogen and progesterone, regulate your cycle, and can be affected by:
- the beginning (puberty) or near the end of a woman’s reproductive years (menopause)
- spotting with ovulation (as a result of hormonal changes)
- starting or stopping birth control: the pill or mini-pill, contraceptive ring, intrauterine device (IUD), injectable contraceptives or implants
- dysfunctional ovaries
- thyroid gland problems
- starting hormone replacement therapy (HRT) after menopause
2. Implantation bleeding.This is when the fertilised egg attaches to your uterus lining.
3. Pregnancy. You can experience IMB after a miscarriage, termination of pregnancy, or ectopic pregnancy.
4. Infections. These include sexually transmitted infections (STIs), like chlamydia and or gonorrhoea, as well as pelvic inflammatory disease.
5. Benign growths, such as a polyp, fibroid, or growth on the cervix, vulva or vagina.
6. Thickening of the endometrium (also called hyperplasia).
7. Polycystic ovary syndrome (PCOS).
8. EndometriosisIt occasionally causes spotting a few days before your period.
9. Medicines, such as blood thinners.
10. Trauma or injury to the skin or tissue of the vagina
For a detailed list of causes and treatments, read Living with Metrorrhagia (Intermenstrual Bleeding)