Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder affecting women of reproductive age, impacting an estimated 5% to 18% of this population. The syndrome is often associated with irregular menstrual cycles, leading to the common perception that having PCOS automatically means a lack of ovulation and infertility. A diagnosis of PCOS does not automatically preclude a woman from ovulating every month, and many individuals with the condition maintain surprisingly regular cycles.
Defining PCOS Through Diagnostic Criteria
The answer to whether a person can have PCOS and still ovulate regularly lies in the established medical guidelines used for diagnosis. The most widely accepted standard is the Rotterdam criteria, which requires a person to exhibit at least two out of three specific features to receive a diagnosis. These three features are hyperandrogenism, oligo- or anovulation, and polycystic ovaries on ultrasound.
Hyperandrogenism refers to clinical or biochemical signs of excess androgens (“male” hormones), such as elevated testosterone levels, hirsutism (excessive hair growth), or severe acne. Polycystic ovaries on ultrasound are defined as having a high number of small follicles, typically 20 or more per ovary, or an increased ovarian volume. The third criterion, oligo- or anovulation, means having irregular or absent menstrual cycles, often defined as cycles longer than 35 days or fewer than nine periods per year.
Since only two of these three criteria are required for a diagnosis, a person can be diagnosed with PCOS while still having regular monthly ovulation. This specific presentation is often referred to as a “phenotype” of PCOS, where the diagnosis is met through hyperandrogenism and polycystic ovaries on imaging, but not through ovulatory dysfunction. Studies suggest that 15% to 25% of individuals with PCOS may experience regular menstrual cycles, demonstrating that the condition is not a universal barrier to ovulation.
Hormonal Drivers of Ovulation Irregularity
For individuals with PCOS who do experience irregular cycles, the root cause is a disruption in the hormonal communication necessary for ovulation. The primary driver of this disruption is insulin resistance, where the body’s cells do not respond effectively to insulin, causing the pancreas to overproduce the hormone. This resulting hyperinsulinemia acts directly on the ovaries, stimulating the cells to produce an excessive amount of androgens.
The elevated androgen levels interfere with the normal follicular development process within the ovary. Normally, the pituitary gland releases luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in a coordinated rhythm to mature a single dominant follicle that will release an egg. High androgens disrupt this feedback loop, preventing the dominant follicle from fully maturing and releasing its egg, resulting in anovulation.
Furthermore, the excess insulin lowers the production of sex hormone-binding globulin (SHBG) in the liver. SHBG typically binds to androgens, making them inactive, so a reduction in this protein increases the amount of free, active testosterone circulating in the bloodstream. This further fuels the hyperandrogenism, creating a self-perpetuating cycle of hormonal imbalance that suppresses ovulation. This explains why individuals with a more severe metabolic component to their PCOS are more likely to experience ovulatory dysfunction.
Strategies for Maintaining a Regular Cycle
For those with PCOS who currently ovulate regularly, the focus shifts to maintaining this hormonal balance to prevent ovulatory dysfunction. Since insulin resistance is a central mechanism in the disorder, lifestyle strategies aimed at improving insulin sensitivity are recommended. Adopting a diet with a low glycemic index can help stabilize blood sugar and insulin levels, reducing the stimulation of androgen production.
This approach prioritizes whole foods, lean proteins, and high-fiber carbohydrates over processed and sugary options. Regular physical activity is another effective strategy for improving insulin sensitivity, even without significant weight loss. A combination of moderate aerobic exercise and resistance training enhances the body’s ability to utilize glucose, regulating hormone levels and supporting menstrual regularity.
Even a modest reduction of 5% in body weight can be sufficient to improve insulin and androgen levels, potentially restoring or maintaining ovulation in those who are overweight. Certain nutritional supplements or medications may also be used to support cycle regularity by targeting the underlying metabolic drivers. Myo-inositol, a naturally occurring substance, has been shown to improve insulin sensitivity and support ovarian function.
For some, a doctor may recommend an insulin-sensitizing medication like Metformin, which can help lower insulin levels and has been shown to decrease hyperandrogenism and improve ovulation frequency, even in lean individuals with PCOS.