Reproductive System & Sexual Health >
Combined Hormonal Contraception
“Combination of synthetic progestogen and oestrogen”
Method of Action
- Combination of synthetic progestogen (progestin) and oestrogen (oestradiol valerate- prodrug or ethinyloestradiol)
- Low oestrogen conc and high progesterone suppress gonadotrophin release
- Gonadotrophin is responsible for follicular releasing hormone and luteinising hormone release from anterior pituitary
- Progestins bind to progesterone receptors
- Induce thick viscid mucous and inhibit LH surge
- Bind to other receptors e.g. gonadotrophin, androgen, oestrogen, glucocorticoid and mineralocorticoid
- Anti-gonadotrophin binding is desirable
- Other receptor binding produces S/E
- Synthetic oestrogen allows better cycle control and bleeding profile by stabilising endometrium, inhibiting FSH release
- Low oestrogen conc and high progesterone suppress gonadotrophin release
Effects
- Fallopian tube
- Reduced cilia beating, contractions
- Ant pituitary and hypothalamus
- Progestin inhibits LH surge
- Oestrogen inhibits FSH release
- Both: inhibit GnRH release
- Endometrium
- Thick viscid mucous induction
- Increase PR receptors
- Asynchronous development
- Cervix
- Progestin causes the thick viscid mucous plug
- Ovary
- Progestin stops ovulation
- Oestrogen stops follicular development
Side Effects
- Blood vessels: ↑ clotting and ↓ antithrombin so ↑ risk of MI/stroke/DVT
- CNS: nausea, mood changes
- Water and sodium retention: oedema, weight gain, breast tenderness
- Hypertension
- Androgenic effects: oily skin, acne, hirsutism, weight gain
- Possible association with breast cancer in short term
Examples
- COCP
- Monophasic e.g. Zoely 24 days active, 4 days placebo
- Biphasic, triphasic and quadriphasic e.g. Qlaria preparations
- CTP: Evra patch weekly then patch free week, release hormones every 24hrs
- Combined vaginal ring: NuvaRing stays in situ for 3 weeks
Contraindications
- CVD
- Obesity
- >35
- Smoking
- Migraines
- Liver disease
- Breast cancer
Protection
- Ovarian
- Endometrial and colorectal cancer
Other Uses
- Reduce menstrual symptoms
- Menorrhagia
- Acne