Menopause

The menopause literally means the last menstrual period. The International Menopause Society (IMS) defines menopause (natural menopause) as (1):

“the permanent cessation of menstruation resulting from the loss of ovarian follicular activity. Natural menopause is recognized to have occurred after 12 consecutive months of amenorrhea, for which there is no other obvious pathological or physiological cause. Menopause occurs with the final menstrual period (FMP) which is known with certainty only in retrospect a year or more after the event. An adequate biological marker for the event does not exist”.

Physiologically, it is characterised by increased production of FSH and LH as negative feedback from serum oestrogen diminishes.

On average, it occurs at 51 years in the U.K., although it can vary between 40 and 58 years of age and it is slightly earlier among smokers (about 2 years earlier than non-smokers) (2).

Sometimes it may be difficult to define precisely when the menopause occurs, especially if the woman begins to take hormone replacement therapy during the menopause.

NICE state that (2):

• diagnose the following without laboratory tests in otherwise healthy women aged over 45 years with menopausal symptoms:
  • perimenopause based on vasomotor symptoms and irregular periods
  • menopause in women who have not had a period for at least 12 months and are not using hormonal contraception
  • menopause based on symptoms in women without a uterus
    
    
• FSH test:
  • do not use a serum follicle-stimulating hormone (FSH) test to diagnose menopause in women using combined oestrogen and progestogen contraception or high-dose progestogen
    
    
  • consider using a FSH test to diagnose menopause only:
    • in women aged 40 to 45 years with menopausal symptoms, including a change in their menstrual cycle
      
      
    • in women aged under 40 years in whom menopause is suspected
      
      
      • diagnose premature ovarian insufficiency in women aged under 40 years based on:
        • menopausal symptoms, including no or infrequent periods (taking into account whether the woman has a uterus) and
        • elevated FSH levels on 2 blood samples taken 4-6 weeks apart

Do not use a follicle-stimulating hormone (FSH) blood test to identify menopause in people using combined oestrogen and progestogen contraception or high-dose progestogen (2)

Do not use the following laboratory and imaging tests to identify perimenopause or menopause in people aged 45 or over (2):

• anti-Müllerian hormone
• inhibin A
• inhibin B
• oestradiol
• antral follicle count
• ovarian volume

Be aware that people from some ethnic minority backgrounds and people with some lifelong conditions may experience menopause at a younger age.

References:

1. The International Menopause Society (IMS). Menopause Terminology
2. Menopause: diagnosis and management. NICE Guideline NG 23.(November 2015 - last updated November 2024)