Lecture 11: Contraception Flashcards
What is the definition of contraception:
A method of preventing pregnancy via interference with ovulation, fertilisation or implantation.
Why is contraception important?
50% pregnancies are unplanned
NZ has 21.3 per 1000 teenagers having kids… unplanned
Whats the law around informed consent and competence? - with regards to contraception
The law: There is no restriction on prescribing contraception to under 16s without parental consent
Informed consent relies on an assessment of competence
What are the theoretical ways of contraception:
- Physical barrier
- Sperm impairment
- Prevent ovulation
- Prevent implantation
Compare and contrast perfect vs typical use of contraceptions:
18% failure rate of condoms with typical use of condoms and 2% with perfect use
Combined oral pill 9% typical use and 0.3% perfect use.
What are the UK Medical Eligibility Criteria:
MEC-1 No restriction on use.
MEC-2 Advantages outweigh disadvantages
MEC-3 Disadvantages outweight advantages
MEC-4 Do not use.
What is the mechanism of action for the combined oral contraception:
COC: Estrogen + Progesterone.
- Suppress ovulation
- Reduce sperm transport in upper genital tract (FT)
- Change in endometrium making implantation less likely
Mainly: Thicken cervical mucus (preventing sperm penetration
How many COC formulations are there?
29 different formulations
- Find the one with least side effects
What are the combined OCP advantages?
- Convenient
- Familiar
- Reversible
- Lighter, less painful periods
- Lower risk of ovarian and colorectal cancer
- In reality this is what most women know, and so it is what they request.
What are the OCP side effects and risks?
- NO EVIDENCE weight gain or depression
- Headaches - mainly pill free interval
- Increase risk of venous thromboembolism
- Increased CVA
- Increased hypertension
- Increased risk of breast cancer
- (CAREful risk assessment required)
What are some medical conditions that are to consider when prescribing combined OCP:
- Focal migraines (MEC4)
- Smoking status
- Weight (BMI 35+ is MEC3)
- Blood pressure
- Poorly controlled diabetes
Why bother with the pill free interval?
- Its not a real period
- Sleeping ovaries awake, FSH rise…
- Cant start next late….
- Side effects more common during this time i.e headache
What are the 3 ways to take the pill:
Period each month (7 days non-hormone pills)
Have period every few months (just have 7 non-hormone pills when you want to have period)
Not have period, take hormone pills continuously
What is the POP?
Progesterone Only Pill
How does the POP work?
Mainly by thickening cervical mucous - Withint 48hrs Ovulation supression may occur - Depends on dose conc. No PFI (hormone free period- which only came about cus of religion)
Useful if unable to take the OCP, or if breast feeding
Noriday and cerazette are two types of POP, decrease them:
Noriday
- Mini pill
- Relies on cervical mucous effect
- 3h window
Cerazette
- Cervical mucus effect
- Higher rate of suppression of ovulation
- 12h window
What are the side effects of POP?
Progesterone effects: Breast, tenderness, headaches, nausea
Irregular bleeding is common, less so with cerazette
Few contraindications compared with OCP
What are LARCs? how do they work?
Long acting reversible contraception
- Administered once month
- Cost effective after one year use
- Main choice of youth
- Training and accessibility i.e cost are issues
How does the depo provera work?
Suppresses hormones responsible for ovulation
Thickens cervical mucus to block sperm
What are the benefits, risk and side effects of depo provera:
12 weekly injections
Prolonged amenorrhoea / irregular bleeding
Progestogenic side effects
Weight gain in some
Reversible dec in bone density
Delayed return to fertility (av six months)
Estrogen free - fewer restrictions than OCP
How does jadelle work?
Prevents implantation
Describe the benefits, risks and side effects of jadelle?
5y lifespan
irregular bleeding
Progestogenic side effects
CI- Breast cancer, allergy to jadelle, undiagnosed vaginal bleeding
Enyme inducing drugs i.e st john wort
How does the copper IUD work?
Sperm impairment
Prevents implantation
What are the benefits, risks and side effects of the copper IUD:
Hormone free Lasts ten years Infection risk exceptionally low Gold standard emergency contraception Periods may be heavier, longer or more painful Expulsion ~5%, perforation 0.1% Increased risk of ectopic (minor)
Can be used as emergency contraception (copper one only)
