Normal Menstrual Cycle
In the United States the average girl starts her period at age 12. Menstrual cycles typically last between 21 to 35 days with 5 days of bleeding. Menopause occurs at an average age of 51.
Periods occurring too frequently
Frequent periods, referred to as polymenorrhea, is diagnosed when the menstrual cycle is shorter than 21 days. Polymenorrhea can be due to many things including perimenopausal status, medications, infections or certain types of contraception.
- Perimenopause: As menopause approaches it is not uncommon for menses to become closer together before spacing out and eventually stopping altogether. Menses can be regulated with contraception, progesterone or one can wait for menopause to occur.
- Medications such as blood thinners can cause irregular vaginal bleeding. Lab work can be done to see if the dose of medication needs to be adjusted.
- Infections such as chlamydia, trichomonas and endometritis can cause vaginal bleeding that may be mistaken for menstrual bleeding. A vaginal swab or biopsy done by your healthcare provider can be done to check for infections. If an infection is present, it can be treated with antibiotics.
- Contraception: Long acting contraception such as an IUD, Nexplanon or Depo Shot commonly causes spotting during the first few months of use. For most people this resolves with time but if it is bothersome, please see your healthcare provider.
Periods not occurring frequently enough
Oligomenorrhea is diagnosed when the menstrual cycle is longer than 35 days. This may be due to immaturity of the HPO axis, perimenopausal status, thyroid disease, pituitary dysfunction, androgen excess, or pregnancy.
- The hypothalamic-pituitary-ovarian axis (HPO axis) is the pathway through which the brain sends messages to the ovaries to stimulate ovulation. During the teenage years this pathway is not yet fully mature which leads to skipped or irregular periods and long menstrual cycles. If it is troublesome, contraception can be used to regulate menses and with time the HPO axis will mature and menses should normalize.
- In adult women, pituitary dysfunction can cause infrequent and irregular menses because the pituitary is part of the pathway between the brain and the ovaries. When that pathway is disrupted, the ovaries do not receive the proper signals to ovulate. Without ovulation, menses become irregular. Your healthcare provider may ask you questions and do a physical exam or lab work to screen for pituitary problems.
- During the perimenopausal phase the menstrual cycle first shortens, periods get closer together, and then lengthens until periods eventually stop. Menses can be regulated with contraception, progesterone or one can wait for menopause to occur.
- Thyroid disease can disrupt ovulation which in turn leads to infrequent and irregular menses. Lab work can be done to check for thyroid disease which is commonly treated with medication.
- Androgen excess is when women have a higher than normal level of male hormones. This can happen most commonly with polycystic ovarian syndrome. Your healthcare provider may ask you questions and do a physical exam or lab work to check for hormonal imbalance.
- Pregnancy is the most common reason for a woman to miss a period. Ruling out pregnancy is the first step in the workup for irregular periods.
Bleeding between periods
Intermenstrual bleeding is vaginal bleeding between periods. This can be as light as spotting or as heavy as a period. It may be due to structural abnormalities such as a uterine polyp, thickening or thinning of the lining of the uterus, thinning of the vaginal tissue, medications or infection.
- A polyp is a small growth of tissue that is usually benign, non-cancerous, that bleeds easily. This can be diagnosed with an ultrasound or a hysteroscopy. Polyps can be removed by a hysteroscopy.
- Thickening of the lining of the uterus is typically due to too much estrogen. An ultrasound may be done to measure the lining of the uterus. A biopsy can be done to ensure the thickening is not due to precancer or cancer of the uterus. Treatment depends on the cause of the thickening.
- Thinning of the lining of the uterus can be due to contraception and is normal after menopause. Progesterone contraception thins the lining of the uterus which causes lighter or no periods however if the lining becomes too thin spotting can occur.
- Thinning of the vaginal tissue occurs after menopause. The tissue becomes more delicate and bleeds more easily when irritated. Your healthcare provider can do a pelvic exam to assess the vaginal tissue. If atrophy is present, medications are available to help moisturize and thicken the tissue.