4.7.13Additional lessons
Hormone Replacement Therapy — IB Biology HL Revision Notes & Topical Questions
5 min read 5 parts Lesson 67 of 101
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 5Menopause
After menopause a woman can no longer ovulate and so cannot conceive naturally.
Definition
- Definition Menopause is the permanent end of menstruation, usually occurring between about 45 and 55 years of age.
Cause
- Cause The ovaries have few remaining follicles and respond less to FSH and LH, so oestradiol and progesterone fall.
Feedback
- Feedback Low oestradiol means weaker negative feedback, so FSH and LH levels rise.
Symptoms
- Symptoms Hot flushes, night sweats, mood changes and vaginal dryness may result, and bone density may decrease.
Section 2 of 5Hormone Replacement Therapy
Aim
- Aim HRT provides oestradiol, sometimes with progesterone, to replace the hormones that the ovaries no longer make.
Delivery
- Delivery It may be given as tablets, skin patches, gels or implants.
Progesterone
- Progesterone Added in women who still have a uterus to reduce the risk of overgrowth of the endometrium.
Duration
- Duration It is usually used at the lowest effective dose for the shortest time needed.
Section 3 of 5Benefits and Risks
Benefits
- Benefits HRT relieves menopausal symptoms and helps to slow loss of bone density.
Cancer risk
- Cancer risk Some forms of HRT are associated with a small increase in the risk of breast cancer.
Clotting risk
- Clotting risk Oral forms may raise the risk of blood clots and stroke.
Individual decision
- Individual decision The balance depends on a woman's age, health and family history, so advice is individual.
| Aspect | Without HRT | With HRT |
|---|---|---|
| Hot flushes | Common | Reduced |
| Bone density loss | Faster | Slower |
| Breast cancer risk | Baseline | Slightly increased with some types |
| Blood clot risk | Baseline | Increased with oral types |
Section 4 of 5Evaluating Evidence
Correlation and cause
- Correlation and cause Early observational studies suggested heart benefits, but later controlled trials did not confirm this.
Sample size and design
- Sample size and design Large randomised trials with control groups give stronger evidence than small surveys.
Changing advice
- Changing advice Medical guidance changes as new data appears, which is an example of how science is self-correcting.
Section 5 of 5Exam Checklist & Tips
4.7.13 – Key Points for the Exam
- Menopause The permanent end of menstrual cycles in women.
- HRT Treatment that supplies hormones to replace those lost at menopause.
- Osteoporosis A condition in which bones lose density and break easily.
- Randomised controlled trial A study in which participants are randomly assigned to treatment or control groups.
Common Mistakes
- Saying that menopause is caused by a lack of FSH; FSH levels rise.
- Claiming HRT restores fertility.
- Describing the risks of HRT as the same for all women and all types.
- Treating a correlation in an early study as proof of cause.
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