Gynae: Contraception Flashcards
What are the types of contraception available?
- Barrier: male/female condoms, diaphragms & caps +/- spermicides
-
Hormonal:
- Combined hormonal: COCP, patch, vaginal ring
- Progesterone only: POP, implant, depot injection, IUS
- IUD (copper)
What is the failure rate of typical use of male condoms?
16%
What is the failure rate of typical use of female condoms?
21%
What is the failure rate of typical use of diaphragms & caps?
16%
Summarise the use of spermicides, how they work & their risks & contraindications
- Used in conjunction with barrier contraception, esp diaphragm/caps (not alone due to low efficacy)
- Jelly/cream/pessary containing nonoynol-9 → poisons any sperm that enter the vagina
- RISKS: May increase STI transmission due to irritation of mucosa
- → contra-indicated in HIV
Name some progestogens used in hormonal contraception
Progestogens can be:
- 2nd generation (levonorgestrel, norethisterone),
- 3rd generation (desogestrel) or
- 4th generation (drospierenone)
What is the name of the oestrogen used in hormonal contraceptives?
- ethinylestradiol
How do combined contraceptives work?
- Combined hormonal contraceptives primarily create a level of oestrogen and progesterone that is constantly inhibitory on the HPG axis
- This prevents the LH surge → prevents ovulation
- Progesterone also:
- inhibits proliferation of endometrium (to prevent implantation)
- increases thickness/acidity of cervical mucus (to prevent passage of sperm)
Name the types of combined contraceptives
- COCP
- patch
- vaginal ring
What are the 2 types of COCP?
- monophasic - most common
- phasic
How are monophasic pills taken? Give some examples
- Every pill contains the same levels of oestrogen and progesterone
- Taken once daily for 21 days, then a 7-day break (withdrawal bleed)
- Microgynon 30: 30ug ethinylestradiol and 15ug levonorgestrel - most common
- Brevinor: 35ug ethinylestradiol and 0.5mg norethisterone
How are phasic pills taken? Give some examples
- Contain varying amount of oestrogen and progesterone across the cycle → can be biphasic, triphasic or quadraphasic depending on the number of different active tablets
- Pills must be taken in the correct order
-
Qlaira: quadraphasic COCP
- Taken every day for 28 days with no break; 26 active pills and 2 inactive
-
BiNovum: biphasic pill
- Taken for 21 days with 7-day break
Describe the contraceptive dermal patch. How is it used?
- combined contraceptive
- 5x5cm patch that can be stuck to the upper arm, abdomen, buttock or back → delivers oestrogen and progestogens
- Changed every 7 days over 3 weeks (21 days), then 7 patch-free days
Describe the use of the contraceptive vaginal ring
- combined contraceptive
- Plastic ring inserted into vagina for 21 days; removed for 7 days
- May be removed for a couple of hours to be cleaned (then replaced)
Advantages of combined contraceptives?
- Highly effective if taken correctly - when taken correctly: >99% effective
- Menses tends to become regular, lighter and less painful;
- Allows control over timing of menses
- E.g. pill can be taken back to back to prevent menses → often advised for women with dysmenorrhoea/headaches during pill-free interval (tricycling – 3 packs back to back)
- Reduces risk of: ovarian/endometrial cancer, benign breast disease, fibroids, functional ovarian cysts
- Normal fertility returns immediately after stopping usage
Disadvantages of combined contraceptives?
- Doesn’t protect against STIs
- User-dependent → missed pills are common
- Side effects and complications
What are the SEs of combined contraceptives?
SEs of all types:
- Headache
- Breast tenderness
- Mood changes
- Weight gain (no evidence)
- Unexpected bleeding → may settle with time
Complications of all types:
- Increased BP
- Increased risk of VTE (related to oestrogen dose; increased with 3rd/4th gen progestogens)
- Small increased risk of stroke, MI, breast/cervical cancer
COCP-specific:
- Headaches on pill-free week → can take back-to-back
Patch-specific:
- Skin sensitivity
Contraindications of combined contraceptives?
- BMI >35
- Breastfeeding
- Smoking over the age of 35
- HTN
- History or FHx of VTE
- Prolonged immobility due to surgery or disability
- DM with complications, e.g. retinopathy
- History of migraines with aura
- Breast cancer or primary liver tumours
What advice must be given on starting combined contraceptives?
- Start on the 1st day of menstruation (no additional contraception needed); otherwise condoms for 1 week
- COCP: take daily for 21d then 7d break; take within 12hr window; can take up to 3 packets back-to-back (tricycling)
- Extra contraception needed for 7 days if taking certain antibiotics or enzyme-inducing drugs
Missed pills, patches and rings:
- Missed pills (incl D&V):
- If taken late (<24hrs): take ASAP, no problems
- If 1 pill missed (24-48hrs late): take ASAP, take remaining pills at usual time
- EC not usually needed → consider if other pills have been missed recently
- If 2 or more pills missed (>48hrs late): take most recent pill ASAP, take remaining pills at usual time, use condoms for 7 days
- Pills missed in 1st week (pills 1-7): consider EC if sex occurred in pill-free interval or in the 1st week of pill taking
- Pills missed in 2nd week (pills 8-14): EC not needed if preceding 7 pills taken correctly
- Pills missed in 3rd week (pills 15-21): omit the pill-free interval by starting a new pack when current pack ends
- Patch not applies for 48hrs/ring not applied for 3hrs → condoms for 7 days
- EC if unprotected sex has occurred
What are the types of progesterone only contraceptives?
- POP
- implant
- depot
- IUS
