Contraception Flashcards
what percentage of women 16-49 who use contraception in the UK use what?
Sterilised - 28%
Combined oral contraceptive pill - 25%
intrauterine methods - 6%
Progestogen only pill - 5%
progestogen only implant or injectable - 3%
what percent of women do not use contraception despite not wanting to become pregnant
12%
what is the pearl index
defined as the number of contraceptive failures per 100 women-years of exposure
looks at the total months or cycles of exposure from 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 is more accurate/used more commonly - the pearl index or life table analysis
life table analysis
what is perfect use
when a method of contraception is used perfectly as directed/prescribed
what is typical use
how a method of contraception is used by the average women(or men) i.e. will skip some pills, forget to get an injection on time, incorrectly use a condom
what are some of the most effective forms of contraception (i.e. smallest difference between perfect and typical use)
progestogen implant: 0.05% - 0.05% unintended pregnancies
Hormonal IUD - 0.1%-0.1%
male sterilisation - 0.10%-0.15%
female sterilisation - 0.5%-0.5%
what are the three main forms of combined hormonal contraception
pill
patch
vaginal ring
what two hormones are in combined hormonal contraception
ethinyl estradiol (EE - synthetic oestrogen) progestogen (synthetic progesterone)
what does of EE is usually in combined hormonal contraception (and with what exception)
20-35 micrograms
BUT 50 if on liver enzyme inducers
how is the OCP usually taken
taken for 21 days with a pill free week for a period
what is the mode of action of the COC
prevents ovulation
prevents implantation
inhibits sperm penetration of the cervical mucus
how does the COCP prevent ovulation
alters FSH and LH so there is no surge
i.e. affects the HPG axis - synthetic hormones stop production of GnRH - in turn stops production of LH and FSH
how does the COCP prevent implantation
by providing an inadequate endometrium - kept very thin
how does the COCP prevent sperm penetration the cervical mucus
alters quality and character of mucus - thickens
how should the COCP be started
if starting day 1-5 of cycle - immediately protective, no barrier contraception needed
if starting any other time of cycle need 7 days with barrier contraception in order to give time for hormones to “switch off” ovaries
what are some non-contraceptive benefits of the COCP
regular bleed
reduction in painful/heavy period
reduces anaemia
reduction in ovarian cysts
50% reduction in ovarian and endometrial cancer
improves acne
reduced benign breast disease, rheumatoid arthritis, colon cancer, osteoporosis
what are some risks of COC use
venous thromboembolism - 25 per 100,000 women year with
oestrogen acts as a pro-thrombotic
what are other factors that can affect risk of VTE
major surgery + immobility thrombophilias FH of VTE in under 45s BMI over 30 underlying vascular disease postnatally within 21 days
what is the POP
progestogen only pill (desogestrel pill - creel/cerazette)
how is the POP taken
one pill taken within 3 hours of the same time everyday without a pill free interval
effect lost if more than 3 hours late - BUT some newer pills have a 12 hour window
what is the mode of action of POP
renders cervical mucous impenerable by sperm - max effect about 48hrs after ingestion
what is the progestogen injection
DepoProvera
an aqueous solution of cystals of the progestogen depomedroxyprogesterone acetate
how is depoprovera given
150mg given deep IM injection into the upper outer quadrant of the buttock every 12 weeks
what is the mode of action of depoprovera
prevents ovulation
alters cervical mucous making it hostile to sperm
prevents implantation by rendering the endometrium unsuitable
what are the pros of depoprovera
good for forgetful pill takers
70% women amenorrhoeic
estrogen free
what are the cons of depoprovera
delay in return to fertility (BUT no reduction in fertility
reversible reduction in bone density
problematic bleeding
weight gain
what comprises the subnormal implant
small plastic rod
- contains 68mg progestogen etonogestrel (ENG)
- covered in a rate controlling membrane made from ethanol vinyl acetate (EVA)
what is the primary mode of action go the implant
inhibition of ovulation
- 100% women
- over 3 years of use
- regardless of weight
what is the secondary mode of action of the implant
effect on cervical mucous
- inhibiting sperm entry into upper repro tract
what does LARC mean
long acting reversible contraception - 5-10 years
what are examples of intrauterine contraception
copper coil
hormonal coil
what is the mode of action of the copper coil
copper is toxic to sperm - effective also as a form of emergency contraception
what is the mode of action of the hormonal coil
affects the lining of the womb - implantation unable to take place
what are the main forms of emergency contraception and which is most effective
copper coil - most effective
levonel - “morning after pill”
ella one
when can ella one be taken
up to 120 hours after unprotected sex
when can level be taken
levonel (levonorgestrel) can be taken up to 72 hours after unprotected sex
when can the copper coil be used as emergency contraception
up to 5 days after unprotected sex or up to day 19 in a cycle
what is female sterilisation and how is it carried out
laparoscopic sterilisation
traditional tube ligation (filshie clips)
what are the failure rates of female sterilisation
1 in 500 lifetime risk for laparoscopic
1 in 200 for mixed occlusion methods
what is a vasectomy
the permanent division of the vas deferens under local anaesthetic - irreversible procedure (low success rates to reverse)
what are the failure rates for a vasectomy
1 in 2000
what are some complications of a vasectomy
pain due to sperm granuloma, mass of degenerating spermatozoa surrounded by macrophages
is a vasectomy immediate interns of protection against pregnancy
no - need to use other contraception until sperm sample confirms procedure has worked
