Hormonal imbalances, non-cancerous uterine growths, and infections can cause bleeding between regular menstrual periods, also referred to as intermenstrual bleeding, according to Healthline. Stress or cervical cancer can also cause the condition.
Premature ovarian failure, a condition in which the ovaries in a woman under the age of 40 fails to function normally, can also trigger menstrual irregularities, according to Mayo Clinic. Birth control pills can often regulate irregular menstruation patterns. It is important for a woman to consult with a physician if she experiences heavy bleeding, bleeding that lasts longer than seven days, or bleeding between periods.
Menstrual periods that occur every two weeks can also indicate perimenopause, a condition that occurs in women prior to the onset of menopause, explains WebMD. Perimenopause can last up to 10 years in certain women and typically begins around the age of 40. Additional symptoms of perimenopause include hot flashes, urinary difficulties or leakage, dryness in the vaginal area, swollen breasts and decreased sex drive. Premenstrual syndrome may also become more severe during this time. While menstrual irregularities are common during this transitional phase, it is still important for women to seek medical attention to rule out potential underlying conditions, such as blood clotting abnormalities or hormonal problems.