Contraception 1 Flashcards
Describe the steps in the menstrual cycle
- On day one low levels of oestrogen stimulate the release of GnRH from the hypothalamus
- GnRH stimulates the pituitary to release FSH
- Follicles in the ovary grow and release oestrogen in response to increased FSH
- Oestrogen levels increase and stimulate proliferation of the endometrium
- Oestrogen levels reach a peak then stimulate the release of LH from the pituitary
- Ovulation occurs with 36 hours of the LH surge and the follicle walls then collapse
- Progesterone then becomes the primary hormone
- Progesterone levels peak 8 days post ovulation
- Progesterone promotes a secretory endometrium - preparing for implantation of a fertilised egg
- In addition to ovulation, oestrogen produces a thin watery muscles to facilitate sperm transport
- Post ovulation progesterone creates a thick sticky mucus which inhibits sperm transport
- Progesterone is also responsible for a slight rise in basal body temp
What are the long acting reversible contraceptive choices?
Levonorgestrel IUS
Copper coil
Progestogen implant
Progestogen injection
What are other forms of contraception?
CHC’s - pill, patch, ring
POP
Male and female condoms
Diaphragm and cap
Fertility awareness
Sterilisation
What oestrogen components do CHC’s contain?
Ethinylestradiol - 20 - 40 micrograms
Estradiol valerate
Mestranol - converted to ethinylestradiol in the gut
What Progestogen components do CHC’s contain?
Levonorgestrel
Norethisterone
Desogestral
Gestodene
Norgestimate
Nomesgestrol acetate
How do CHC’s work?
- They inhibit ovulation
- Both oestrogen and Progestogen work on the hypothalamic-pituitary axis preventing release of FSH and LH
- With no surge in FSH or LH ovulation does not occur
- Cause thickening if the cervical mucus producing a barrier to sperm
- Prevent implantation of a fertilised ovum due to decreased proliferation of the endometrium
Contraceptives should not be prescribed…
Generically
What type of preparation is not recommended in the NI Formulary?
Phasic - more complicated and no real benefit
What is the NI Formulary first choice for Monophasic standard strength CHC?
Rigevidon - 30 micrograms of ethinylestradiol and 150 levonorgestrel
1 daily for 21 days followed by a 7 day pill free interval
What is the NI Formulary second choice for Monophasic standard strength CHC?
Gederal 30/150 - 30 micrograms ethinylestradiol and 150 micrograms desogestral
Or
Cilique - 35 micrograms ethinylestradiol and 250 micrograms norgestimate
Or
Millimetre 30/75 - 30 micrograms ethinylestradiol and 75 micrograms gestodene
1 daily for 21 days then 7 day interval
What is the NI Formulary first choice for Monophasic low strength CHC?
Gedarel 20/150
Or
Millinette 20/75
How does the patch work?
- Avoids FPM
- Similar efficacy to oral CHC
- Produces plasma levels similar to that of oral CHC w/o peaks and troughs
- Apply to clean dry skin avoiding breast area
- Patches are worn for 7 days and then changed - repeated for 3 weeks then 7 days break
- Reserved for women where compliance is an issue
- Ethinylestradiol and norelgestromin
How does the vaginal ring work?
- Self insertion into vagina - remains in place for 21 days then patient has a 7 day break before inserting a new ring
- Avoids FPM
- Nuvaring - ethinylestradiol and etonogestrel
What are the tailored regimens?
Only work with monophasic designed to be taken 21/7
- Shortened HFI - 21 days - 4 day HFI
- Extended use - 9 weeks - 4 or 7 HFI
- Continuous use - continuous - no HFI
What are the risks with CHC?
- Increased risk of VTE
- risk factors = prolonged period of immobility, obesity, increasing age, fam history and smoking
- should be discontinued 4 weeks prior to elective surgery - Increased risk of cervical and breast cancer
- breast reduced after discontinuing CHC
- cervical risk associated with use >5 years
- cervical risk reduces over times and no longer present after stopping for 10 years - Arterial disease
- use associated with increased risk of stroke and MI
- avoid if following RF = obesity (BMI > 30kg/m2), mild - mod hypertension, diabetes mellitus, smoking, fam history - Migraines
- must ask an migraine history
- increased risk of ischameic stroke if migraine/migraine with aura - alt cont