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Compared effectiveness of different contraceptives - are condoms enough protection? watch

    • Thread Starter

    Thought I would produce a (hopefully) educating thread on the failure rates of various contraceptives, particularly that of condoms.

    A pearl index = rate of failure of a contraceptive method expressed in 100 women years.
    Basically it represents the number of women out of a 100 will fall pregnant within a year when using that form of contraception. I haven't seen it mentioned as to whether regular sex is a condition of the index.

    I got this my info from a lecture which took its info from the uk national statistics website, the data is from 2008/9 I believe.
    There is also a comparative table on this page: wiki comparison
    Some of the stats on there are conflicting with mine, some corroborating. They are taken from american studies so may involve a different population, different trial set-up and so on. It's the general gist you want to come away with I think.

    So here are the pearl indices (this is the important part if the rest is TL/DR):

    Fertile, not using any contraception = 80
    Spermicides (alone) = 4-25
    Coitus interruptus = 8 - 17
    Male condom = 2 - 15
    Female condom = 2- 15
    COC* = 0.1 - 3
    POP* = 0.3 - 4
    Depo Injection = 0 - 1
    Implanon = 0 - 1
    Mirena = <0.5
    Male sterlilisation = 0 - 0.2
    Female sterlisation = 0 - 0.5

    * COC = combined (oestrogen and progestogen) oral contraceptive
    * POP = progestogen only pill

    If you and your partner are young, the chances are you are very fertile so you're going to be looking at the very lowest values only if you are using that contraceptive perfectly every time.

    I was really surprised that condoms have such a high value.

    Another statistic: If a couple aren't using any protection and having regular sex, still only 1 in 5 cycles (ovulations) will actually result in a pregnancy. That is to say the actual rate of a contraceptive failing to protect (where someone could have got pregnant) is going to be higher than the pearl index (through "luck" essentially). Exposure is much higher than pregnancy fallout.

    And if you're taking that into account, exposure to STDs over a year (possibly with different partners) using condoms, could be much higher than the Pearl Index for condoms of 2 - 15.

    Something to think about given I would say the take-home message of sex ed at school (for me at least) was "use condoms then you'll be safe". Not really true (by my interpretation).


    2 - 15 percent? Couldn't they work out an exact average percentage?

    I always assumed condoms were promoted because, aside from the obvious pregnancy/std protection, they're easily accessible, especially to young people.
    You can get them wherever, whenever and easily without having to make a commitment to a more long term contraception, which is obviously involved with the pill/injection/implant etc.

    So regardless of if they aren't as effective as you think, they're just the most convenient method surely?
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