Contraception Flashcards
What types of contraception are being used in the UK?
- Sterilise (28%)
- Combined oral contraceptive pill (25%)
- Intrauterine methods (6%)
- Progesterone only pill (5%)
- Progesterone only implants/ injectable (3%)
What are the features of the ideal contraceptive?
- 100% reversible
- 100% effective
- 100% convenient and unrelated to intercourse
- 100% free of adverse side-effects
- 100% protective against STIs
- Non-contraceptive benefits
- Low maintenance and no-ongoing medical input
How do contraceptive clinical trials typically report their failure rates?
By the pearl index or life table analysis
What is the pearl index?
- ThePearl Indexis defined as the number of contraceptive failures per 100 women-years of exposure.
- It looks at the total months or cycles of exposure from the initiation of the product to the end of the study
What is the life table analysis?
Provides the contraceptive failure rate over a specified time-frame and can provide a cumulative failure rate for any specific length of exposure.
What form does the combined contraceptive come in?
- Pill
- Patch
- Vaginal ring
How effective is the COC?
Over 99% effective = Pearl index 0.3 - 4.0 per HWY
What does the COC contain?
It is an orally active pill combination of 2 hormones
- Ethinyl estradiol (EE)
- Synthetic progesterone (progestogen)
What is the usual dose of the COC?
Usual dose 20 – 35 microgram EE (50 if on liver enzyme inducers)
What are the second generation COCs?
- Levonorgestrel (LNG)
- Noresthisterone (NET)
What are the third generation COCs?
- Gestodene (GSD)
- Desogestrel (DSG)
How is the COC usually taken?
-Taken for 21 days and then a pill free week
What is the mode of action for the COC?
- Prevent ovulation
- Alters FSH to LH so there is no surge
- It prevents implantation by providing an inadequate endometrium
- It inhibits sperm penetration of the cervical mucus by altering quality and character of mucus
How is a surge of LH and FSH prevented when using the COC?
Negative feedback of oestrogen and progesterone on the hypothalamus preventing LH and FSH release
How is the COCP taken effectively?
- Start day 1 but up to day 5 without barrier contraception
- Takes 7 days to switch off ovaries
- Use condoms for first 7 days
- 21 days and stop fro 7
- Contraceptive protection remains
- Can use continuously for 3 months then pill free week
What are the non-contraceptive benefits of the COCP?
- Regular bleed with a potential reduction in painful heavy menstruation and anaemia
- Reduction in functional ovarian cysts
- 50% reduction in ovarian and endometrial cancer
- Improvement in acne
- Reduction in benign breast disease, rheumatoid arthritis, colon cancer and osteoporosis
What are the risks associated with the COCP?
- VTE
- Very small increase in ischaemic stroke and increased further in those with focal migraine
- Breast cancer risk is likely to be small and disappears 10 years after stopping COC
- Cervical cancer risk apparently doubles with 10 years use
-No increase in risk of MI in non-smokers
What is the absolute risk of VTE contraception?
- 5 per 100,000 women years in the general population
- 15 per 100,000 women year with COC use (LNG and NET)
- 25 per 100,000 women years with COC use (GSD and DSG)
- 60 per 100,000 women years with pregnancy
What is the relative risk of VTE with COCP?
Risk increases 3 fold
What are the risk factors for VTE?
- Major surgery and immobility
- Thrombophilias
- -Family history of VTE in those under age 45 years
- BMI over 30
- Underlying vascular diseases
- Postnatally within 21 days
- COCP
What is the effectiveness of the progesterone only pill?
Pearl index of 0.3-3.1 = over 99% effective but it is user dependent.
Why does the POP have lower failure rates in older women?
They are less fertile and perhaps less sexually active.
Give an example of a POP?
Desogestrel pill
How is the desogestrel pill taken.?
- 12 hour window period
- Traditional pills taken within 3 hours of the same time every day without a pill-free interval