Polymenorrhoea is the medical term for frequent menstrual periods. Women with polymenorrhoea have normal pain-free periods, but they occur very frequently. It is not considered to be a problem unless the periods occur more often than every 24 days, and treatment is often reserved for those women in whom it occurs more often than once every three weeks.
It is important todistinguish from polymenorrhoea the small breakthrough bleed that may occur at the time of ovulation in the middle of some women’s monthly cycle. These mid-cycle bleeds are usually only 12 to 36 hours in length, and are characterised by minimal blood loss. A similar breakthrough bleed can occur while taking an oral contraceptive pill that is too low in hormone dose for that woman.
Frequent periods can be caused by a disturbance to the pituitary gland under the brain,
which is releasing the ovary-stimulating hormones at the incorrect time. In other women, damaged ovaries (e.g. due to cysts) may be the cause of polymenorrhoea.
The only practical treatment for polymenorrhoea is the oral contraceptive pill, as this can hold the hormone levels at an artificially high level until the period is desired (usually every 28 days). If the woman objects to the use of the pill, other hormones may be used, but they are not generally as effective.