Perimenopause Guide
CURRENT GUIDANCE UPDATE
Definition of Perimenopause
Perimenopause is defined as the period beginning with the first menopause symptoms and continuing until 12 months after the final menstrual period.
Early Symptom Onset
Perimenopause commonly starts in the mid-40s, and symptoms may appear 4–8 years before menstrual periods become irregular.
AMH & Ovarian Reserve
Anti-Müllerian Hormone (AMH) is the most sensitive marker of declining ovarian reserve but should not be used alone to diagnose perimenopause.
Individual Assessment
Diagnosis should be based primarily on age, menstrual history and symptoms, with laboratory testing reserved for selected clinical situations.
Introduction
What Happens During Perimenopause?
As ovarian reserve declines, follicle-stimulating hormone (FSH) levels rise as the pituitary gland works harder to stimulate the remaining follicles. Oestrogen levels fluctuate significantly—sometimes rising above normal and sometimes dropping sharply within the same cycle. This hormonal instability, rather than consistently low oestrogen, is responsible for many perimenopausal symptoms.
Often Before Irregular Periods
- Worsening PMS or PMDD symptoms
- Breast tenderness and swelling
- Menstrual cycles becoming shorter
- Heavy menstrual bleeding
- Anxiety or increased emotional sensitivity
- Sleep disturbance and insomnia
- Palpitations or awareness of heartbeat
As Hormonal Changes Progress
- Irregular and unpredictable periods
- Hot flashes and night sweats
- Mood instability or depression
- Brain fog and concentration problems
- Vaginal dryness
- Reduced libido
- Joint and muscle aches
Clinical Assessment
Perimenopause is primarily diagnosed using age, symptoms and menstrual history. FSH levels above 30 IU/L on two tests 4–6 weeks apart suggest ovarian decline, although values fluctuate widely. AMH reflects ovarian reserve but is not diagnostic on its own. Women under 45 with symptoms may require hormonal testing to exclude premature ovarian insufficiency.
Treatment & Lifestyle Support
- Cyclical combined HRT for symptom relief and cycle regulation
- Combined oral contraceptive pill for women needing contraception
- Continue contraception until 2 years after the last period if under 50, or 1 year if over 50
- CBT, SSRIs/SNRIs and lifestyle measures for non-hormonal symptom control
- Vitamin D and calcium to support long-term bone health
Frequently Asked Questions
I'm 43 with no irregular periods but I have hot flashes and anxiety — could this be perimenopause?
Yes. Symptoms frequently precede menstrual irregularity by several years. Worsening PMS, new anxiety, sleep disturbance, and hot flashes in the mid-40s are consistent with early perimenopause. Clinical assessment and a hormonal profile are appropriate.
Do I still need contraception if I'm perimenopausal?
Yes. Ovulation continues intermittently during perimenopause and pregnancy is possible until natural menopause is confirmed. Contraception is required until 2 years after the last period for women under 50, and 1 year for women over 50.
Conclusion
Perimenopause is a phase that many women navigate with insufficient information and support. Earlier recognition, accurate diagnosis, and evidence-based management of perimenopausal symptoms significantly improves quality of life during this transition.
Sources & References
This article draws on guidance current at the time of writing from the following bodies and publications:
- RCOG (2023)
- NICE NG23 (2023)
- IMS (2022)
General reference bodies for women's health guidance:
RCOG
rcog.org.ukACOG
acog.orgFIGO
figo.orgWHO
who.intNICE
nice.org.uk⚠ IMPORTANT DISCLAIMER
This article is provided for general knowledge and reference purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. No medication, treatment, or change to your healthcare should be undertaken based on this content without first consulting a qualified doctor. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition.
