The average menstrual cycle is 28 days, but anything from 25 to 35 days is thought to be normal. Small changes from month to month are common, but your cycle should generally be the same every month.
Oligomenorrhea is when you often don’t get your period for 35 days or more and as a result have only four to nine periods each year. Missing a single period that is not due to pregnancy, birth control, or menopause is normally not cause for alarm. But if you regularly go 35 days or more between periods, you should talk to your doctor.
How Common Is Oligomenorrhea?
Oligomenorrhea occurs in about 13.2% of persons who menstruate. This number increases to 20% among those with existing fertility issues.
Causes of Oligomenorrhea
Many things can cause oligomenorrhea. Even though it is not considered a disease, oligomenorrhea might be a symptom of underlying health problems like:
- Polycystic ovarian syndrome — or PCOS. PCOS causes imbalance in female hormone levels, along with formation of fluid-filled cysts on the ovaries and production of more than usual amounts of male hormones — called androgens. Up to 10% of women in the United States may have PCOS.
- Cushing syndrome. In Cushing syndrome, your body makes too much of the hormone cortisol or gets too much cortisol from certain medications.
- Prolactinoma. Prolactinoma is a noncancerous tumor that causes your pituitary gland — a small gland at the base of the brain — to make too much prolactin. Prolactin is the hormone needed for milk production after pregnancy. Prolactinomas can make up 40% of all tumors in the pituitary gland and can lead to infertility.
- Congenital adrenal hyperplasia. This is a genetic disorder that affects your adrenal glands and leads them to have insufficient amounts of enzymes that are needed to make specific adrenal hormones.
- Pelvic inflammatory disease — or PID. PID is usually seen if you leave a sexually transmitted disease untreated.
- Asherman's syndrome. Women with Asherman's syndrome have scar tissue in their uterus or cervix that can cause fertility problems.
- Primary ovarian syndrome. This condition was formerly called premature menopause or premature ovarian failure. In this condition, your ovaries begin to behave differently. They may not release an egg or produce estrogen and progesterone as they should.
- Hyperthyroidism. Hyperthyroidism is a disorder where the thyroid makes too much of thyroid hormones, which enter your blood and affect your menstrual cycle.
- Eating disorders. Bulimia, anorexia, binge eating, and other eating disorders can cause harm to your body, including your reproductive systems.
You might also get oligomenorrhea from other factors like:
Your doctor will start with a physical examination to check for any lumps, tender areas, or extra body hair. A vaginal speculum examination is another important test in which your vaginal walls and cervix are checked for infection, inflammation, scar tissue, or growths.
After the physical examination for oligomenorrhea, your doctor may request blood work to check your hormone, blood sugar, and protein levels. Your doctor may test one or more of the following:
- Thyroid-stimulating hormone (TSH)
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Hemoglobin A1C
Depending on the results of your examination and blood work, additional tests may be done including CT scan, ultrasound, cervical swab, and MRI.
Treatment of Oligomenorrhea
The treatment plan for oligomenorrhea varies depending on the underlying cause. You might have to make lifestyle changes to reduce stress and improve your diet or get hormone therapy pills. Other oligomenorrhea treatment plan options may include medication tailored to the condition. If you have a tumor, your doctor may recommend surgery to remove it.
Risks of Oligomenorrhea
If untreated, oligomenorrhea can lead to various health concerns, including osteoporosis, acne, cardiovascular issues, neurological disorders, infertility, endometrial hyperplasia (when too many cells build up in the uterine lining), or endometrial cancer.
To keep your reproductive health in good shape, speak to your doctor if you have any concerns about your monthly periods.