Contraception Effectiveness
(stats taken from Toronto Notes 2008. For more details about each method, go here)
Chance
- nothing used...just flying by the seat of your pants and rolling a 10-sided dice every time = 10.0%
Female condom = 75.0%
Withdrawal method/coitus interruptus = 77.0%
Rhythm method/calendar/mucous/symptothermal = 76.0%
Spermicide along = 82.0%
Diaphragm w/ spermicide = 90.0%
Condom alone = 90.0% (assuming proper use which often doesn't happen)
Condom w/ spermicide = 95.0%
NuvaRing (once-a-month hormonal contraceptive) = 98%
Depo-Provera = 99%
Hormonal skin patch > 99%
Oral Contraceptive Pill = 98.0-99.5% (depends on compliance)
Tubal ligation = 99.6%
Vasectomy = 99.8%
Abstinence = 100.0%
What I don't understand is how the surgical methods (tubal ligation and vasectomy) aren't 100%? If you tie off the tubes and do a little snip-snip, how can the sperm still get there and induce a pregnancy 0.2-0.4% of the time? Another category I didn't include are the emergency postcoital contraceptive (EPC) methods, also referred to as the "morning-after pill". By taking a large bolus of progestin or combo estrogen/progestin after the fact within 24 hrs, they will terminate any potential pregnancy 98% of the time (you can take it up to 72 hrs after I think). I wouldn't say they prevent a pregnancy because technically fertilization may have taken place in the uterine tubes at that point - they just do a very good job at making sure it doesn't progress any further. I think there are some serious ethical implications of EPC methods that separate it from the other classes of contraception.
If you don't want to be starting a family anytime soon, maybe it's time to consider how effective your chosen method of contraception is and make changes as necessary...
Labels: School
4 Comments:
Cool, Matt! Do you have stats on all of the above in regards to STI prevention also? Just cuz I'd almost rather get pregnant than get HIV or cervical cancer or a lifetime of genital warts.
Also, percentages are all well and good until you're the 1 in 10 who used the condom correctly but got pregnant anyways. Yikes.
Hey Meera!
I haven't found any stats for STI prevention but if I come across some I will definitely pass it on.
don't ask me about the mechanism behind it but from what i know, in some cases the fallopian tubes in tubal ligation or the ductus deferens in a vasectomy can actually reconnect. seriously. it's like it's got a mind of it's own! that's scary man.
Ya that's what we learned too, it just grows back on it's own sometimes. Creepy.
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