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
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How Are Irregular Periods Defined?

Most normal periods, on average, are between 28 and 32 days. Anything shorter than 21 days or longer than 35 days is considered to be irregular.

Some women with PCOS may have a regular monthly cycle each month. Yes, you can have PCOS and have regular periods. 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 have irregular, absent, or oligoovulation. 

Oligoovulation is when ovulation occurs infrequently or irregularly, and usually, is classified as having 8 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 (more than 50 days). 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 ovarian failure (or 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. Generally, it's not good if you're not shedding your uterine lining each month. This can cause a build-up in the endometrial lining, increasing the risk of uterine cancer.

Some doctors 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 doctor’s attention. Further diagnostic testing and/or medical intervention may become necessary.

Updated by Angela Grassi, MS, RDN, LDN

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