Menopause and Physiology Overview

Study Notes

Menopause is the permanent cessation of menstruation, occurring on average around age 51.
A retrospective diagnosis is made after 12 months without periods.
Perimenopause describes the period before and after menopause, often characterized by vasomotor symptoms and irregular periods.
It typically occurs in women older than 45 years and spans a year before and after the final menstrual period.
Premature menopause occurs before the age of 40 due to premature ovarian insufficiency.

Follicles inside the ovaries mature into primary and secondary follicles independent of the menstrual cycle.
FSH stimulates follicle development, leading to oestrogen production by granulosa cells.
Menopause begins with a decline in follicle development, resulting in reduced oestrogen production.
Oestrogen's negative feedback effect on the pituitary gland suppresses LH and FSH production.
Falling oestrogen levels during perimenopause lead to increased LH and FSH as there is no negative feedback.
Anovulation and irregular menstrual cycles occur due to failing follicle development.
The lack of oestrogen causes amenorrhoea and perimenopausal symptoms.

Reduced oestrogen levels increase the risk of:
- Cardiovascular disease and stroke
- Osteoporosis
- Pelvic organ prolapse
- Urinary incontinence

Perimenopause and menopause can be diagnosed in women over 45 with typical symptoms without investigations.
NICE guidelines recommend an FSH blood test for:
- Women under 40 with suspected premature menopause
- Women aged 40-45 with menopausal symptoms or changes in menstrual cycles

Fertility declines after age 40, but women should still be considered fertile.
Pregnancy after age 40 carries increased risks and complications.
Women should use effective contraception for:
- Two years after the last period for women under 50
- One year after the last period for women over 50
Hormonal contraceptives do not affect the menopause itself, but can suppress and mask symptoms, making diagnosis difficult.
Suitable contraceptive options include:
- Barrier methods
- Mirena or copper coil
- Progesterone-only pill
- Progesterone implant
- Progesterone depot injection (under 45 years)
- Sterilisation
Combined oral contraceptives (UKMEC 2) can be used until age 50 if no contraindications exist in women over 40.
- Consider pills containing norethisterone or levonorgestrel in women over 40 due to lower venous thromboembolism risk.
Progesterone depot injection (e.g. Depo-Provera) can lead to weight gain and reduced bone mineral density, making it unsuitable for women over 45.