Contraception Flashcards
What are the ideal characteristics of a contraceptive?
- 100% reversible
- 100% effective (NONE)
- 100% unrelated to intercourse
- 100% free adverse side effects (NONE)
When can sex cause pregnancy?
If 26-32 day cycle and not on hormonal Rx
Likely ovulate day 12-18
Egg survives 24 hours
Most sperm survive <4 days
Highest chance of pregnancy from sex days 8-19
BUT variable so methods can fail even if abstain on fertile days
Describe combined hormonal contraception (pill, patch, vaginal ring)
Combination of two hormones; ethinyl estradiol (EE) and synthetic progesterone (progestogen)
Stop ovulation, also affect cervical mucus and endometrium
Tailored regimes;
- pill taken daily (anytime in 24 hours)
- patch EVRA changed weekly
- ring nuvaring changed every three weeks, can be taken out for 3 hours in 24 so can take out for sex
What are the non-contraceptive benefits of combined contraceptives?
Regulate/reduce bleeding; help heavy/painful periods
Stop ovulation; may help PMS
Reduction in functional ovarian cysts
50% reduction in ovarian and endometrial cancer
Improve acne
Reduction in benign breast disease, RA, colon cancer and osteoporosis
What are some side-effects of the combined contraceptives?
- breast tenderness
- nausea
- headache
- irregular bleeding first 3 months
Describe the progesterone only pill (POP/”mini-pill”)
Take at same time EVERY DAY without a pill-free interval
Not good if frequent GI upset
What are side effects of the progesterone only pill?
Varibable
- appetite increase
- hair loss/gain
- mood change
- bloating/fluid retention
- headache
- acne
No increased risk venous or arterial thrombosis with contraceptive dose
Still avoid if current breast cancer or liver tumour past/present
Describe the injectable progesterone contraceptive
Aqueous solution of progestogen
150 mg 1ml deep intramuscular injection into upper outer quadrant buttocks every 13 weeks
- Prevents ovulation
- Alters cervical mucus making hostile to sperm
- Makes endometrium unsuitable for implantation
Benefits of injectable progesterone contraceptive
Only need to remember every 12 weeks
70% women amenorrhoeic after 3 doses
Oestrogen free so few contraindications
Cons of injectable progesterone contraceptive
Delay in return to fertility; average 9 months
Reversible reduction in bone density
Problematic bleeding especially first two doses
Weight gain 2/3 women gain 2-3kg (the only contraceptive with CAUSAL effect on weight gain)
Give details about the subdermal progestogen implant (the ‘rod’)
A 2mm by 40mm “rod”
Core; 68mg etonogestrel (ENG)
Membrane; ethinyl vinyl acetate (EVA) 0.06 mm thick (this is rate controlling)
What are the benefits of the progestogen implant?
Inhibition of ovulation + effect on cervical mucus
Can last 3 yrs - or be removed at any time
No user input needed
No causal effect on weight
What are the cons of the progestogen implant?
60% almost blood free but have prolonged/frequent bleeding
May cause mood change more often than other progestogen only methods
Describe the IUD (‘the coil’) and benefits
Long acting reversible contraception (LARC) ; 5-10 years use
Little user input after fitting, can be fitted any age
Effects/side effects immediately reversible when removed
What are the cons of the IUD?
Very small infection risk in first three weeks (<1:1000)
Fitting takes 10 minutes - usually GP/SRH clinic
5:100 risk expulsion; check threads after each period
If conceives may be ectopic but method so effective the risk lower than for condoms
