Menstrual cycle hormones: a GP guide to oestrogen and progesterone
The menstrual cycle is regulated by a coordinated pattern of hormone changes, primarily involving oestrogen, progesterone, follicle-stimulating hormone (FSH) and luteinising hormone (LH). These hormones naturally rise and fall throughout the cycle and influence physical symptoms, mood, energy levels and bleeding patterns.
This page explains how menstrual cycle hormones work, what is considered normal variation, how GPs assess hormone-related symptoms, and when testing is helpful.
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.
The main hormones involved in the menstrual cycle
Oestrogen
Oestrogen is produced mainly by the ovaries and plays a key role in:
- Thickening the lining of the uterus
- Regulating the menstrual cycle
- Supporting bone health
- Influencing mood, skin and energy levels
Oestrogen levels rise in the first half of the cycle and peak just before ovulation.
Progesterone
Progesterone is released after ovulation and helps:
- Prepare the uterus for a potential pregnancy
- Stabilise the uterine lining
- Influence sleep, body temperature and mood
Progesterone levels rise in the second half of the cycle and fall if pregnancy does not occur, triggering a period.
FSH and LH
FSH and LH are produced by the pituitary gland and control ovarian function.
- FSH stimulates egg development early in the cycle
- LH triggers ovulation
These hormones fluctuate in a predictable pattern in regular cycles.
Hormone changes across the menstrual cycle
The menstrual cycle is usually divided into phases:
Follicular phase
- Begins on day one of the period
- Oestrogen levels gradually rise
- Many people feel more energetic during this phase
Ovulation
- Triggered by a surge in LH
- Usually occurs mid-cycle
- Fertility is highest around this time
Luteal phase
- Progesterone levels rise
- Body temperature increases slightly
- Some people notice lower energy or mood changes
Common symptoms linked to cycle-related hormone changes
Hormonal fluctuations can contribute to:
- Breast tenderness
- Bloating
- Headaches
- Mood changes
- Changes in energy or concentration
Mild symptoms are common and usually part of normal cycle variation.
When symptoms may need further assessment
GP review may be helpful if symptoms are:
- Severe or worsening
- Affecting daily functioning
- Associated with very irregular, absent or heavy periods
- Accompanied by other concerning features
Conditions such as premenstrual syndrome (PMS), premenstrual dysphoric disorder (PMDD), polycystic ovary syndrome (PCOS) or perimenopause may be considered depending on the pattern.
How GPs assess hormone-related cycle concerns
Assessment usually includes:
- A detailed menstrual history
- Symptom timing across the cycle
- Medical and medication history
- Consideration of stress, sleep and lifestyle factors
Blood tests are used selectively and interpreted carefully.
Hormone blood tests and timing
Hormone testing may include:
- FSH, LH and oestrogen, usually early in the cycle
- Progesterone in the second half of the cycle to confirm ovulation
Testing without correct timing can lead to misleading results.
Not everyone with symptoms needs hormone testing.
What hormone tests can and cannot tell you
What they can help with
- Assessing ovulation
- Identifying hormonal conditions
- Supporting referral decisions
What they cannot do
- Explain all menstrual symptoms
- Predict future fertility
- Replace clinical assessment
Normal hormone results do not always mean symptoms are not real.
Hormone balance and life stages
Menstrual cycle hormones naturally change:
- In adolescence
- After pregnancy
- During perimenopause
- With illness, stress or weight change
GPs consider age and life stage when interpreting symptoms and results.
When to seek GP review
Consider GP review if:
- Periods are very irregular or absent
- Symptoms significantly affect quality of life
- You have concerns about hormone test results
- You are planning pregnancy or experiencing cycle changes
Further Reading and Hub Links
Visit our Hormone Health hub or browse more health topics in the AccessGP Knowledge Base.
If you have concerns about menstrual cycle symptoms or hormone balance, a GP can assess your symptoms and advise on appropriate investigation or management.
Last reviewed by Dr Zamiel Hussain, GMC registered GP
Clinical contributor: Dr Tasnimah Miah, Women’s Health Advocate
Updated: 31 December 2025