Oligoovulation and PCOS

Polycystic ovary syndrome (PCOS) affects at least 10% of women of childbearing ages in the United States. PCOS is characterized by high levels of testosterone (all women have testosterone just like all men have estrogen) creating an imbalance of female sex hormones. In fact, PCOS is the most common cause of ovulatory infertility due to the hormone imbalance seen with the condition.

Having irregular periods is a symptom of PCOS. However, there are many things that can cause irregular periods, and PCOS is not the only one.

Doctor discussing oligoovulation with patient
Cirou / Getty Images

How Are Irregular Periods Defined?

Most normal periods, on average, occur approximately every 28 days. Anything shorter than 24 days or longer than 38 days is considered to be irregular.

Sometimes periods can be too frequent—occurring several times a month or lasting for weeks at a time. Heavy bleeding can cause women to become anemic or have low iron levels. However, most women with the condition have irregular, absent, or oligoovulation. 

Oligoovulation is when ovulation occurs infrequently or irregularly, and usually, is classified as having eight or fewer periods in a year. Normally, a woman ovulates or releases a mature egg once a month, about halfway through her cycle. Because of the hormone imbalance, eggs don't mature or get released like they should be and can cause infertility. Oligoovulation is seen in women with irregular cycles or very long cycles. This may make it difficult to track your fertile days if trying to conceive.

Causes of Irregular Periods

PCOS is diagnosed when a woman has irregular periods in addition to signs of elevated androgens, either by her symptoms or through blood testing. Symptoms of high testosterone (one type of androgen) include abnormal hair growthhair loss, and acne.

If you are a teenager who has only recently gotten her first period, or an older woman approaching menopause, irregular cycles are very common because your hormones are fluctuating. If you lose a significant amount of weight or are under a lot of stress, your periods may be affected as well.

Medically speaking, hypothalamic amenorrhea, pregnancy, and other hormonal conditions can all cause irregular or absent periods. It’s even possible for a woman to be born with a structural abnormality that can prevent her from getting a period, such as not having a uterus or cervix.

Treatment for Irregular Periods

There are many different ways to treat irregular periods or oligoovulation in PCOS depending on your goals and health history. If you're not shedding your uterine lining each month, it can cause a buildup in the endometrial lining, increasing the risk of uterine cancer.

Some healthcare providers recommend oral contraceptives to balance out hormones and create a regular cycle. Although not indicated for this reason, Metformin can also help some women to regulate their cycle.

Women with PCOS can experience regularity to their menstrual cycle through weight loss, changes to their eating, and exercise. In addition, the dietary supplement inositol has been shown to be helpful to regulate periods and balance hormones in women with PCOS.

If your periods suddenly become irregular or if they never become regular as a teenager, you should bring it to your healthcare provider’s attention. Further diagnostic testing and/or medical intervention may become necessary.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Nicole Galan, RN
Nicole Galan, RN, is a registered nurse and the author of "The Everything Fertility Book."