Your menstrual cycle is much more than a monthly period—it is one of the most important indicators of your reproductive health. While every woman is different, your cycle can provide valuable insight into how your hormones are functioning, whether you are ovulating regularly, and whether there may be an underlying condition affecting your fertility. Occasional changes to your cycle are common and can occur due to stress, illness, or lifestyle changes. However, periods that are consistently irregular, very infrequent, unusually long, or absent altogether should not be ignored. Understanding what your cycle is telling you is often the first step towards protecting your reproductive health and achieving your fertility goals.
What Is Considered a Normal Menstrual Cycle?
A “normal” menstrual cycle can vary from person to person. For most women, cycles occur every 21 to 35 days, with bleeding lasting between 2 and 7 days. While some variation is expected, your cycle should generally follow a predictable pattern.
It may be worth seeking medical advice if your periods:
- Occur more than 35 days apart
- Are absent for several months (and you are not pregnant)
- Are highly unpredictable from month to month
- Last significantly longer than usual
- Are accompanied by other symptoms such as excessive hair growth, acne, or unexplained weight changes
These symptoms may indicate that you are not ovulating regularly or that there is an underlying hormonal condition that requires assessment.
Why Regular Ovulation Matters
For pregnancy to occur naturally, ovulation usually needs to happen regularly. When ovulation is irregular or doesn’t occur at all it can become much more difficult to conceive. Irregular menstrual cycles are often one of the earliest signs that ovulation may not be occurring consistently. Even if pregnancy is not your immediate goal, understanding why your periods are irregular is important for your overall reproductive and long-term health.
Common Causes of Irregular or Absent Periods
There are many reasons why menstrual cycles may become irregular. Some of the more common causes include:
Polycystic Ovary Syndrome or Polyendocrine Metabolic Ovarian Syndrome (PMOS)
Polycystic Ovary Syndrome (PCOS) also referred to by some experts as Polyendocrine Metabolic Ovarian Syndrome (PMOS) is one of the most common causes of irregular periods. PCOS is a hormonal and metabolic condition that can affect ovulation, fertility, insulin resistance, weight, skin health, and long-term wellbeing. Many women with PCOS experience infrequent or absent ovulation, making it more difficult to conceive without support.
Thyroid Disorders
Both an underactive thyroid (hypothyroidism) and an overactive thyroid (hyperthyroidism) can disrupt the hormones that regulate the menstrual cycle. Treating thyroid conditions often helps restore more regular cycles.
Significant Weight Changes
Rapid weight loss, significant weight gain, or being significantly underweight can all affect hormone production and ovulation. Even modest improvements in overall health may help restore normal menstrual function in some cases.
Excessive Exercise or Chronic Stress
High levels of physical training or ongoing emotional stress can interfere with the hormonal signals that trigger ovulation. This does not mean that everyday stress causes infertility, but prolonged physical or emotional strain may contribute to cycle changes in some women.
Premature Ovarian Insufficiency (POI)
Premature ovarian insufficiency occurs when ovarian function declines before the age of 40. Women with POI may experience increasingly irregular periods or periods that stop altogether and may require specialist assessment and management.
Don’t Assume “It’s Just Normal for Me”
Many women live with irregular periods for years because they have always been that way. It’s common to hear: “My periods have never been regular.” “I just thought that was normal for me.”
While some women naturally have slightly longer or shorter cycles, consistently irregular or absent periods are often worth investigating. Your menstrual cycle is one of your body’s most important health indicators, and changes to it can provide valuable clues about your hormones, metabolism, and reproductive health.
When Should You Seek Medical Advice?
It may be time to speak with your GP or a fertility specialist if:
- Your periods occur less frequently than every 35 days
- Your periods have stopped altogether
- Your cycles are consistently unpredictable
- You have been trying to conceive without success
- You have symptoms such as acne, excess facial or body hair, hair thinning, or unexplained weight changes
- You have concerns about your fertility or hormone health
Early assessment often includes reviewing your menstrual history, hormone blood tests, ovulation assessment, and pelvic ultrasound where appropriate. These investigations can help identify the underlying cause and guide the most appropriate treatment.
Understanding Your Cycle Is the First Step
Your menstrual cycle tells an important story about your reproductive health. Whether your goal is to conceive now, preserve your fertility for the future, or simply understand why your periods are irregular, seeking advice early can provide reassurance, clarity, and a personalised plan. You do not need to ignore the signs or simply hope your cycle will regulate on its own. Understanding the cause is the first step towards finding the right treatment and supporting your long-term reproductive health.