PCOS and your cycle – how it affects the chance of pregnancy

For women with PCOS (polycystic ovary syndrome), the menstrual cycle may be irregular or completely absent at times. This can make it harder to identify ovulation and to know when you have the best chance of conceiving. In this article, you will learn how PCOS affects your cycle and what you can do to better understand it.

The normal cycle
A typical menstrual cycle lasts between 23 and 35 days and consists of four phases: the menstrual phase, the follicular phase, ovulation and the luteal phase. When the cycle functions regularly, it is easier to calculate your most fertile days. 

PCOS and an irregular cycle
PCOS can mean that ovulation happens less frequently or not at all. Many women experience:
• Irregular or long cycles
• Missing periods for several months
• Changes in bleeding patterns – from very light to very heavy bleeding

When ovulation does not occur regularly, it can be difficult to find the most fertile days. 

See our range of products for cycle tracking with PCOS

Why the cycle is important if you want to conceive
Ovulation is essential for pregnancy. With PCOS, it is often unpredictable when – or if – ovulation will take place. That is why it is helpful to combine several methods of tracking your cycle instead of relying only on counting days. This way you increase the chance of identifying your fertile window.

Methods for tracking your cycle with PCOS
• BBT method – by measuring your basal body temperature every morning, you can see if ovulation has occurred. Read more in The BBT method with PCOS
• Cervical mucus – changes in mucus can give signals that ovulation is approaching.
• Calculators and tests – Ovulation tests can give more precise results. However, many women with PCOS may experience false positives because LH levels are often elevated.
• Combining methods – particularly relevant with PCOS, where cycles are very irregular. Many women use the Sympto-Thermal method, combining BBT tracking with cervical mucus observation. 

PCOS, weight and how weight loss can affect the cycle
Many women with PCOS experience challenges with weight and blood sugar regulation. This is often due to insulin resistance, where the body releases more insulin to keep blood sugar stable. Elevated insulin can affect hormone balance and lead to irregular ovulation.

Research shows that even a modest weight loss – often 5 to 10% of body weight – can positively affect the cycle. For some women, this means that ovulation happens more regularly and the chance of pregnancy increases.

Helpful strategies include:
• Focus on protein and vegetables at every meal
• Choose whole grains instead of refined carbohydrates
• Exercise regularly – both strength and cardio can make a difference
• Eat balanced meals to keep blood sugar stable

You can also read about the KISS diet, developed by gynecologist Bjarne Stigsby, in our article KISS diet: Food that may increase your chance of pregnancy 

If weight loss feels difficult, it can help to start with small steps and focus on sustainable lifestyle changes rather than quick fixes.

What you can do to support your cycle
Although PCOS cannot be cured, you can take steps to support hormone balance and your cycle:
• Keep blood sugar stable through a diet rich in protein, vegetables and whole grains
• Stay active – both strength training and cardio can help
• Prioritize sleep and stress management
• Consider relevant supplements – for example inositol, omega-3 or B vitamins. Read more in PCOS and fertility – supplements that may support your cycle

See our supplements that may be relevant if you want to support your cycle naturally 

When to seek help
If you experience very irregular cycles or absent periods for longer periods of time, it is a good idea to consult a doctor. Many women with PCOS do become pregnant – some spontaneously, others with the help of lifestyle changes, supplements or fertility treatment.