Menstrual cycle & period symptoms

Changes in the menstrual cycle are a common reason to speak with a GP.
This page outlines how variations in timing, flow or symptoms may present, what patterns are considered normal, and when further assessment or testing is appropriate.

These articles are intended as educational sources, not diagnostic nor taking place of a proper medical assessment. If you need help, please book an appointment with one of our GP’s.

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What this page covers

This section explains common menstrual cycle concerns discussed in primary care, including:

cycle length changes
irregular or unpredictable periods
painful periods
heavy or light bleeding
spotting between periods
missed or infrequent periods
early perimenopausal cycle changes
hormonal influences such as thyroid, prolactin or PCOS
when blood tests or pelvic ultrasound may be considered

Common reasons adults speak to a GP

People may notice menstrual changes at different times of life. Common consultation reasons include:

cycles becoming shorter or longer than usual
a period arriving early or late
increased cramps or discomfort
heavier or lighter bleeding than usual
bleeding between periods
infrequent or absent periods
uncertainty about what is “normal” cycle variation
wanting assessment for possible hormonal imbalance
wanting guidance on whether tests or monitoring are needed

A GP reviews symptoms in context, explores patterns and underlying causes, and advises when lifestyle changes, monitoring or investigations may help.

Understanding menstrual cycle changes

1. Normal variation in the menstrual cycle

Cycle length can vary from month to month. Typical ranges include:

21 to 35 days for most adults
up to 7 days of natural variation between cycles
mild changes with stress, illness, travel or disrupted sleep

These variations are usually harmless. A cycle diary or period-tracking app can help identify trends.

2. Irregular or unpredictable periods

Irregular periods occur when the cycle length varies significantly, or when bleeding is sporadic.
Potential GP-relevant causes include:

stress or weight change
thyroid imbalance
elevated prolactin
polycystic ovary syndrome (PCOS)
perimenopause
some medications

A GP may ask about cycle patterns, mood, skin changes, weight change, energy levels and other hormonal symptoms.

3. Heavy, light or prolonged bleeding

Changes in bleeding volume can result from hormonal fluctuations or benign uterine conditions.

Examples include:

heavy bleeding (menorrhagia)
unusually light bleeding
prolonged periods lasting more than 7 days

GPs may consider a pelvic exam, blood tests for anaemia, thyroid function and hormonal markers, or pelvic ultrasound if symptoms persist.

4. Painful periods (dysmenorrhoea)

Cramps may be mild and short-lived, or more severe and disruptive.

Potential causes include:

natural uterine contractions
increased inflammation around menstruation
conditions such as fibroids or endometriosis (if progressive or worsening)

GP assessment focuses on symptom severity, duration, and how much the pain affects daily life.

5. Spotting between periods

Light bleeding between cycles may relate to:

hormonal fluctuations
ovulation-related spotting
contraceptive changes or missed pills
cervical irritation

A GP may review patterns, conduct a cervical screening history and consider examination or ultrasound depending on symptoms.

6. Infrequent or absent periods (oligomenorrhoea / amenorrhoea)

When cycles become very infrequent or stop altogether, common non-pregnancy causes include:

PCOS
thyroid dysfunction
raised prolactin
perimenopause
low body weight or high training volume
chronic stress

Blood tests may be offered to understand the underlying hormonal picture.

AccessGP work with blood tests to help you

How a GP assesses menstrual cycle symptoms

GPs consider:

symptom timing and duration
cycle tracking patterns
pain severity and impact
associated symptoms such as fatigue or mood change
relevant medical or contraceptive history

Investigations may include:

full blood count
thyroid function tests
prolactin
FSH/LH/oestrogen (if appropriate)
androgens (for suspected PCOS)
pelvic ultrasound (for irregular bleeding, heavy periods or pelvic pain)

Managing infections at AccessGP knowledge base

When to seek medical review

You should speak to a GP if you notice:

bleeding that is unusually heavy or lasts more than 7 days
sudden changes from your usual cycle pattern
severe or worsening pelvic pain
bleeding between periods or after intercourse
cycles that become very infrequent or absent
symptoms affecting daily life, energy levels or wellbeing

If you experience severe abdominal pain, dizziness or fainting, seek urgent medical care.

Irregular periods
Heavy or painful periods
Premenstrual symptoms (PMS and PMDD)
Perimenopause symptoms