Menstrual Health

Irregular Periods: Causes, Symptoms & When to See a Gynaecologist in London

Irregular periods are one of the most common concerns women bring to a gynaecologist. An irregular menstrual cycle is defined as one that varies by more than 7 to 9 days from month to month, arrives fewer than 21 days apart, or takes longer than 35 days. If your periods have changed pattern, stopped, or become unpredictable, there is usually an identifiable cause and effective treatment is available in London.

Irregular Periods in Numbers: How Common Is This?

Irregular cycles are more widespread than many women realise. These figures illustrate the scale across the UK and why specialist care matters.

What Are Irregular Periods?

Irregular periods, medically known as oligomenorrhoea (infrequent periods) or amenorrhoea (absent periods), describe a menstrual cycle that does not follow a predictable pattern. A normal cycle ranges from 21 to 35 days, with natural variation of up to 7 to 9 days from month to month. Anything beyond that, consistently, is classed as an irregular menstrual cycle.

An irregular cycle does not always mean something serious is happening. But it should not be ignored long-term. In many cases it signals a hormonal or structural issue that responds well to treatment once the cause is identified.

What Does an Irregular Cycle Look Like?

Signs that your cycle may be irregular include:

• Cycles shorter than 21 days or longer than 35 days
• Period length varying by more than a week from one month to the next
• Missing periods for one month, two months, or more
• Spotting or light bleeding between periods
• Very light or very heavy periods alternating unpredictably
• No clear pattern to when your period arrives

What Causes Irregular Periods?

Irregular menstrual cycles are nearly always driven by hormonal disruption, a structural condition within the uterus, or a combination of both. Below are the most common causes seen at Mr Karoshi’s London clinic.

1. Polycystic Ovary Syndrome (PCOS)

PCOS is the single most common cause of irregular periods in women of reproductive age. It causes the ovaries to produce excess androgens, which disrupts ovulation. Without regular ovulation, periods become infrequent, light, or stop entirely. Around 1 in 10 women in the UK are affected by PCOS.

2. Thyroid Disorders

Both an underactive thyroid (hypothyroidism) and an overactive thyroid (hyperthyroidism) interfere with the hormones that control the menstrual cycle. Hypothyroidism often causes heavier, more frequent periods. Hyperthyroidism tends to make periods lighter, less frequent, or absent.

3. Stress and Elevated Cortisol

High psychological or physical stress raises cortisol. Elevated cortisol suppresses GnRH, the hormone that triggers ovulation. Without ovulation, periods become irregular or stop. This is sometimes called hypothalamic amenorrhoea.

4. Significant Weight Changes

Both rapid weight loss and obesity affect oestrogen levels. Very low body weight, particularly from excessive exercise or restrictive eating, can stop periods entirely. Excess weight increases oestrogen and can also disrupt the cycle.

5. Perimenopause

In women over 40, irregular periods are often a sign of perimenopause, the transitional phase before the menopause. Hormones fluctuate, leading to cycles that are longer, shorter, heavier, or lighter. This is a natural process but symptoms can be managed effectively with specialist support.

6. Endometriosis

Endometriosis, where tissue similar to the uterine lining grows outside the womb, disrupts the normal menstrual cycle and often causes irregular, painful, and heavy periods. Around 1 in 10 women in the UK are affected.

7. Uterine Fibroids or Polyps

Non-cancerous growths inside or around the uterus can alter the regularity and flow of periods. Mr Karoshi is a recognised specialist in fibroid management in London and can assess and treat these conditions.

8. Hormonal Contraception

Starting or stopping the pill, implant, hormonal coil, or injection can disrupt the cycle for several months. This is usually temporary, but persistent irregularity warrants investigation.

Quick Reference: Causes of Irregular Periods at a Glance

Symptoms of an Irregular Menstrual Cycle

The symptoms you notice alongside a change in cycle pattern often provide important clues to the underlying cause.

• Periods arriving with no consistent gap between them
• Cycles that are much shorter or longer than they used to be
• Spotting or light bleeding between periods
• Periods that are heavier or much lighter than your normal
• Painful cramps that are new or getting worse
• Bloating or pelvic pressure around when a period would be expected
• Absence of periods for 3 or more months, not due to pregnancy
• Fatigue, especially if periods are very heavy or very frequent
• Changes in skin, hair, or weight alongside the cycle change

How Are Irregular Periods Diagnosed?

At Mr Karoshi’s London gynaecology clinic, diagnosis follows a clear, structured process designed to get to the root cause efficiently.

Step 1: Detailed Consultation

Mr Karoshi takes a thorough history including cycle pattern, when the irregularity started, associated symptoms, lifestyle, medical history, and fertility goals. This conversation shapes the entire investigation.

Step 2: Blood Tests

Targeted blood tests assess FSH, LH, oestrogen, progesterone, testosterone (if PCOS is suspected), thyroid function (TSH, T3, T4), prolactin, and AMH (ovarian reserve). Results often point directly to the cause.

Step 3: Pelvic Ultrasound

A transvaginal or abdominal ultrasound allows Mr Karoshi to assess the ovaries for signs of PCOS, check for fibroids or polyps, and examine the womb lining. This is a quick, comfortable scan carried out at the clinic.

Step 4: Further Investigation If Required

Where needed, additional tests such as MRI, hysteroscopy, or endometrial biopsy may be recommended to confirm the diagnosis or rule out other causes.

How Are Irregular Periods Treated in London?

Treatment is matched to the specific cause. There is no single approach that suits every woman, which is why accurate diagnosis matters before any treatment begins.

Hormonal Therapy

The combined oral contraceptive pill is often used to regulate cycles where no immediate fertility goal exists. It establishes a predictable hormone pattern and reduces cycle-related symptoms. Other options include the progesterone-only pill or hormonal coil.

PCOS Management

For PCOS, treatment focuses on lifestyle changes (weight management, dietary adjustment, regular exercise), hormonal regulation, and sometimes metformin to improve insulin sensitivity. Women with PCOS who are trying to conceive may benefit from ovulation induction.

Thyroid Treatment

Where a thyroid disorder is identified, it is treated directly. As thyroid levels normalise, the menstrual cycle usually regulates without further gynaecological intervention.

Treating Endometriosis or Fibroids

Where endometriosis or fibroids are the cause, Mr Karoshi discusses the full range of options from medical management to minimally invasive surgery. He is experienced in advanced fibroid treatments including Sonata radiofrequency ablation, which avoids open surgery.

Lifestyle and Wellbeing Changes

For cycles disrupted by stress, excessive exercise, or weight changes, lifestyle adjustments are central to recovery. Mr Karoshi provides clear, practical guidance as part of every consultation.

Treatment Options: At a Glance

When Should You See a Gynaecologist About Irregular Periods?

Not every unusual cycle requires specialist input immediately. A single irregular month after illness or travel is rarely cause for alarm. The following situations do warrant a consultation.

• Your cycles have been consistently irregular for 3 or more months
• You have gone 90 days or more without a period and are not pregnant
• Irregular periods are accompanied by pelvic pain, bloating, or unusual discharge
• You are trying to conceive and your periods are unpredictable
• You have symptoms of PCOS such as excess facial hair, acne, or unexplained weight gain
• You are over 40 and noticing significant changes to your cycle
• You have had investigations elsewhere but still have no clear diagnosis
• The irregularity is affecting your daily life, wellbeing, or fertility plans

Why Choose Mr Mahantesh Karoshi in London?

Choosing the right private gynaecologist in London makes a significant difference to your experience and outcomes. Here is what distinguishes Mr Karoshi’s practice.

Conclusion

An irregular menstrual cycle is not something to dismiss or wait out indefinitely. Whether your periods are arriving unpredictably, stopping altogether, or changing in a way that concerns you, there are clear causes and effective solutions.

The most common causes of irregular periods are well understood and respond well to the right treatment. What matters is an accurate diagnosis from a specialist who takes time to understand your full picture before recommending anything.

Mr Mahantesh Karoshi has spent more than 33 years helping women in London and across the UK understand and manage menstrual disorders. His approach is to provide clear answers, honest guidance, and treatment that is right for you. Not a one-size-fits-all plan.