progesterone based contraceptives Flashcards
what is the mode of action of the contraceptive implant?
releases progesterone
main mechanism of action is to inhibit ovulation.
It also thickens the cervical mucus, inhibiting the passage of sperm to the uterus, and thins the endometrium, preventing implantation were an egg to be fertilised.
what are the contraindications of the implant?
- Already pregnant
- Taking certain medications. Some enzyme-inducing drugs may make the implant less effective – e.g. medications used in HIV, tuberculosis, epilepsy and the herbal remedy St John’s Wort.
- Women with a history or current status of the following:
> Arterial disease, history of stroke or serious heart disease.
> Liver disease
> Breast cancer
> Unexplained vaginal bleeding
what are the advantages of the implant?
99% effective.
Can be used in women for whom the combined oral contraceptive pill is contraindicated.
Provides long-term contraception
Can be used when breastfeeding.
Normal fertility returns as soon as implant is removed.
Effective in women of all body mass (although earlier replacement recommended in women with high BMI).
May reduce the risk of endometrial cancer.
what are the disadvantages of the implant?
Irregular bleeding patterns (affects ~50% of women)
Fitting and removing the implant may cause some pain, bruising and irritation.
Small increased risk of breast cancer.
The implant can sometimes bend or break in situ.
what is the contraceptive injection?
synthetic progesterone is slowly released into systemic circulation following intramuscular (IM) or subcutaneous injection.
There are currently three available in the UK, the most commonly used one being Depo-Provera®.
This is the most commonly used progesterone only injectable and is licensed for long term use. It is given every 12 weeks by deep IM injection.
what is the mechanism of action for progesterone based contraceptives?
Progesterone only injectables prevent pregnancy by the inhibition of ovulation and the thickening of cervical mucus.
The high progesterone also causes thinning of the endometrium making it unfavourable for implantation if fertilisation was to occur.
what are the advantages of the injection?
A very effective form of contraception.
Users don’t have to think about contraception for as long as the injection lasts.
No known interactions with any drugs.
It can be used when combined hormonal contraceptives are not recommended such as in women with migraine and who are breast feeding.
Can be used in women with a BMI < 35.
May reduce the risk of endometrial cancer.
what are the disadvantages of the contraceptive injection?
Not rapidly reversible – can take up to a year to return to normal fertility and menstruation can take several months to return to normal.
Up to 50% of women stop usage within a year due to altered bleeding patterns including persistent bleeding.
Increase in body weight, up to 2-3kg over a year.
May be a slightly increased risk of breast cancer.
Loss of bone mineral density with long term use (over a year of use), although there is no evidence that it increases the risk of fracture.
perfect use = 99% effective, typical use = 94% effective
what are the contra- indications of the injection?
Current Breast cancer (within 5 years)
History of severe arterial disease or very high risk factors
Pregnancy
Diabetes with any vascular disease e.g. retinopathy
People who will want to return to fertility in the near future
what are the advantages of the POP (progesterone only pill)?
More effective than barrier methods when taken correctly.
Sex doesn’t need to be interrupted to use contraception.
Can be used in many patients for whom the combined oral contraceptive is contraindicated.
May reduce risk of endometrial cancer.
perfect use = 99% effective, typical use = 91% effective
what are the disadvantages of the POP?
User dependent and has to be taken at the same time each day.
Can produce irregular menstruation (4 in 10 women) or amenorrhoea (2 in 10 women).
Some adverse affects, such as headaches, breast tenderness and skin changes, may be experienced when POCP’s are first started.
30% increased risk of ovarian cysts.
Small increased risk of breast cancer.
what are the contraindications of the POP?
Current or past history of breast cancer.
Liver cirrhosis or tumours.
Lower efficacy in women over the weight of 70kg.
Stroke or coronary heart disease.
what is the intrauterine system (IUS)?
a small, progesterone releasing plastic device that is placed into the uterus
what are the advantages of the IUS?
works for 3-5 years
periods often become lighter, shorter and less painful
can be used for lactating mothers
high efficacy over 99%
fertility returns quickly after discontinuation
can be used for emergency contraception
Reduces the risk of ovarian cancer and endometrial cancer
Lower risk of pelvic inflammatory disease
what are the disadvantages of the IUS?
irregular bleeding or spotting is a common side effect in 6 months following implantation
slight increase in breast cancer risk
