Friday Weird Science: Condoms and ‘Blunt Puncture’

This is actually a Friday Weird Science repost from the old blog. I’ve had a few requests to do something on condom breakage, though, in the words of Dr. Pal “I think a lot of the time when “the condom broke” they really mean it was in the dresser drawer.” It’s true, I’ve never actually heard of a condom busting WIDE OPEN in the middle of sexual intercourse. Condom slippage, I’ve heard of.
But condoms do break, the question is: why?
ResearchBlogging.org White, Hill, Bodemeier. “Male condoms that break in use do so mostly by a “blunt puncture” mechanism” Contraception 77,2008 360-365.
The best thing about this study by far? Showing it to the other people in the lab. I especially recommend showing the “coital simulator” around.


Unbelievable as it may be for a scientist, it seems that I need to get out more. The scientist larval stage, or “grad student” is rarely seen outside the labs, but last night I ventured outside my known territory in the company of a few other larvae. When not in the lab, the larval stage of the scientist doesn’t tend to move very far, stopping to rest and refuel at bars for long periods of time before continuing on.
One of my fellow grad students brought up something truly awesome last night: A study covered in Nature News on condom breakage.
Condom failure is a relatively rare phenomenon, about 0.4-2% for rubber condoms and 0.6-6% for synthetic, though the actual breakage number in a 1000 use study is usually less than 10. Of course, numbers are easy to obtain, what is hard to figure out is WHY the condoms are breaking. Is it lubrication? Is it strength? Is the user completely incompetent or naive? Broken condoms are not usually returned (it is fairly easy to imagine why) to the study centers, so it’s hard to study exactly why condoms are breaking, and so it’s hard to improve the condoms.
So this study analyzed 972 USED condoms that had been returned as consumer complaints, washed and disinfected them (Glad they disinfected, at least), and analyzed them for location of breakage and type of breakage that had occurred. They also conducted a survey to ask those who had not returned broken condoms why the condoms had broken. Finally, to evaluate WHY the condoms were breaking, they made this:
penis.jpg
They refer to it as a “simple mechanical coital model”. Unfortunately they fail to give dimensions for the model, describing it only as “physiologically accurate”, but to me that thing looks like it’s over two feet long!!! At least it looks like that if it’s sitting on the floor and those are windows. But I think that’s an outlet over there, so I guess it’s roughly normal size.
So what did they find?
Of the condoms they received, 474 were actually broken, 203 had some other defect (they do not say what), and another 290 were not actually defective. Most of the condoms were broken in the “teat” area (the closed end), which is not surprising, as that is the part of the condom receiving the most mechanical stress. But some of the condoms showed breakage, not at the tip, but as a kind of eruption through the side wall.
condom.jpg
A condom with ruptured tip.
They got about a 50% reply rate for the survey, finding that 97% of condoms had broken during intercourse, without any reports that “unusual or athletic practices were taking place” (heh, heh. I wonder what rate of condom breakage happens when things are especially ‘athletic’?). 92% on users reported that they did not use any other lubricant (some, like petroleum jelly or mineral oil, can weaker condoms).
Looking for possible mechanisms of breakage, the researchers repeated stretched condoms over a “condom demonstrator” (which is used in condom factories and looks like a large test tube). Repeated stretching did eventually cause breakage, and they noted that after several stretchings, the amount of force required to break a condom is actually fairly low.
They did notice that failures could be broken down into several types, though none appeared to be due to manufacture, and it is believed that “users are breaking normal…condoms because of the circumstances that arise during an individual act of intercourse”. Eruption punctures, those causing holes in the walls or tip during use, appear to be caused by the penis pushing through the intact wall, a process they called “blunt puncture”.
With the use of their coital model, they determined that breakage could be caused when the condom was stretched over the tip of the penis model (in other words, by not leaving a little reservoir of space at the end), with lots of lubrication inside, little lubrication outside, and a tight fit between artificial penis and artificial vagina. By classification of the returned condoms, they found that 90% of failures could be accounted for by “blunt puncture”.
condom graph.jpg
So what does this mean? It means the pointy end of…you…goes in the pointy end of the condom. Not the side, not the wall of the condom. The pointy end. It also basically means that, to have condoms with ‘blunt puncture’, you basically have to be putting it on in an incompetent manner. It also implies, however, that repeated stretching can weaker the latex. So if you stretch it MORE than once, you might want to use another one.
Finally, any scientific study is good if you include a coital simulator. I can only imagine the grad student who got to make that thing from scratch. Should they ever meet Sci, they are getting a beer on me for being AWESOME.
WHITE, N., HILL, D., & BODEMEIER, S. (2008). Male condoms that break in use do so mostly by a “blunt puncture” mechanism☆ Contraception, 77 (5), 360-365 DOI: 10.1016/j.contraception.2008.01.014

27 Responses

  1. I shared this post with a friend, and her reaction deserves to be posted here:
    “Isn’t it fascinating to know that people too fucking dumb to realize how condoms go on are more likely to breed? TAKE THAT, DARWIN!”

  2. And this person Darwin, who is he/her? And what is this person suppose to be taking?

  3. It also basically means that, to have condoms with ‘blunt puncture’, you basically have to be putting it on in an incompetent manner.

    Or making an incompetent choice of condom in the first place. For instance, if the condom’s too small for you, you’re not going to get a proper reservoir space at the end no matter how you put it on. I broke a lot of condoms when I first started using them, but resizing solved the problem completely. (I’m pretty sure I’m not huge or anything, just didn’t fit that particular make & model.)

  4. I broke a condom once. It was definitely on correctly, fitted correctly, no “athletic” activities, and the thing just popped like a balloon.
    No pregnancy resulted (I was 18 at the time), but it scared the bejesus out of both of us.

  5. That is indeed a power outlet behind the right-hand end of the machine. It’s a pair of British three-pin sockets, and the box is about six inches across, so the artificial phallus is pretty much life size.
    Has anyone nominated these guys to the Ig-Nobel committee?

  6. Now now, machines can’t simulate everything. They’ve got to bring in test subjects and see what happens…
    Now that would be an awesome study.
    PS Isn’t it possible that some of the side breaks were during oral sex? (I’m thinking teeth, specifically, which would fall on the side of the condom instead of the tip)

  7. I broke one once, just peeled back from the tip like a banana.
    …. It was a rather “athletic” performance.

  8. So for those of you who DID have condoms break, was the end result a hole like the one pictured above? Or did it look different? And, to a get a little more personal, were there obvious problems with lubrication? They mention problems with lubrication was being one of the things that can cause puncture.

  9. One condom breakage in about 18 years of (intermitent) use. Nothing unusual about brand, lubrication, installation, or athleticism. It just shredded backwards, more on one side than the other, making about a 3″ tear.

  10. I’m not sure that your reading of this study actually implies what you say it does. To deduce that when a condom fails, it must be because the user(s) put it on in an incompetent manner seems a far leap from any evidence you provide. (Unfortunately I can’t access the full study.) The only information you provided was that repeated stretching will weaken the condom, which seems to be common sense. But you quote “users are breaking normal…condoms because of the circumstances that arise during an individual act of intercourse”. How, then, do you surmise that users are incompetent? Seems a pretty bold assumption from a scientist. Your following paragraph is very unclear as to the point you’re trying to make, but I find it noticeably absent that there’s little mention or exploration of the fact that “92% of users did not use any other lubricant.” You follow this observation by correctly pointing out that oil-based lubricants can break down latex, but there’s no mention that using additional water- or silicone-based lube could actually reduce the likelihood that a condom will break; such that simply by not adding lube (even to an already lubricated condom), you’re in effect increasing the chances that it will break. I’m not necessarily arguing with the premise that user error is the cause of condom breakage, but there’s nothing in your piece that seems to imply this is the case. All I can deduce is that “blunt puncture,” which sounds more like someone sticking a needle in the condom than a penis, was what caused the breakage.

  11. I’m not sure if I’m exceptionally unlucky or my boyfriend’s penis has some sort of quirk but we’ve had several condoms break over the course of a year and a half.
    Not just the puny little tear at the top either… These things were TORN ASUNDER! A piece was left on the head like a little hat, with the rest crumpled at the base.

  12. Forgot to add: as far as lubrication problems go, there are a few (I don’t produce a whole bunch of natural lube as it is), but we usually used a water-based lubricant.

  13. Jonathan: thanks for your comments. The authors do specify that “blunt puncture” would not be the result of something like a needle (which is, of course, not blunt). It was caused by repeated mechanical stress on an area of the condom not meant to handle it. In particular, it specifically mentioned that the coital simulator damaged condoms when no room was left in the tip, which means that repeated mechanical stress in this area may have contributed to the blunt puncture. To put on a condom in this way, without leaving room in the reservoir, is (to me) to put it on incorrectly. Thus, incompetence.
    Of course I am sure that many condom breaks do occur without people being incompetent. You certainly can’t make perfect layers of latex every time, and I’m sure there are some condoms with weak spots. It’s possible that this study, finding the majority of breaks occur at the tip, could promote studies into increasing thickness of the latex around the area of breakage.
    But you are right that the authors of the study should probably have studied the effects of lubricant or lack thereof on condom breakage. What they say in the study is that condom breakage will occur most often when there is more lubricant on the inside of the condom relative to the outside, which apparently causes more mechanical strain.
    I would be glad to send you a copy of the paper if you want it. Also, I’m not an engineer and I don’t study the effects of mechanical stress. So it’s very possible I could have missed something. But I still think that the cases in which “mechanical stress” was the cause of breakage, resulting either from no room left in the reservoir or from lack of lubrication on the outside vs the inside, could easily be the result of incompetence, either putting on the condom incorrectly, or not using (or…stimulating) the proper amount of outside lubricant.

  14. Holy crap, Zan! Switch brands or something! That doesn’t sound good.

  15. LOL! Condom wear and tear (heh).
    Also, best experimental apparatus evah!! “Oh that? That’s for the experiments. No! It’s not for frustrated grad students!”

  16. …and I thought my research was sexy!

  17. So for those of you who DID have condoms break, was the end result a hole like the one pictured above?

    Usually, if we realized what was happening quickly enough and stopped. If we didn’t realize and continued, then it would eventually peel farther back. (This was rather frustrating at the time, because, well, both of us would immediately notice an improvement in sensation. It got to the point where I would use “Wow, this just went from feeling good to feeling really good” as a cue that I should stop and check for a break.)

    And, to a get a little more personal, were there obvious problems with lubrication?

    Not in our case, but there were problems with tightness of fit, as the study mentions. We were both inexperienced and it was some time before she was able to “unclench” on demand.
    Even after that point, though, the condom almost always broke until we went up a size.

  18. A partner and I had a condom break in a way that sounds somewhat similar to this (the “lots of lubrication inside” part sounds familiar to that fella’s preferences). We both knew what we were doing, thanks, but impatience may have been a factor. The business end of the thing ripped up completely rather than resembling the photo. Fortunately, it’s not hard to detect this kind of failure since it does change the feel of the thing, so the failed part was swapped out with no harm done.

  19. Hah! I admit it has a certain crude appeal, but best apparatus evah? You shoulda seen the rig we built back in ’75 to test artificial hip joints – glued into real femurs, and trailing wires from dozens of strain gauges.
    The leg assembly sat in the heart of a whirling, gyrating cage of hydraulically-driven actuators, and that thing could boogie when it simulated someone running a hundred-yard dash, I can tell you!

  20. Hmmm, providing all the scientifically relevant details may be a little bit TMI or embarrassing to post as a comment here for the Guglz to keep forever. Perhaps you should ask people to e-mail you, or even set up an online survey, make it ‘private’ and perhaps allow people to post anonymously there so you can collect enough information for a graph and a blog post.

  21. Hmmm, providing all the scientifically relevant details may be a little bit TMI or embarrassing to post as a comment here for the Guglz to keep forever. Perhaps you should ask people to e-mail you, or even set up an online survey, make it ‘private’ and perhaps allow people to post anonymously there so you can collect enough information for a graph and a blog post.

    … *snicker*
    I can’t recall that we’ve ever had one break, but we’ve only used them when there was some issue with her hormonal birth control.

  22. Perhaps the broken condoms that were returned were used by beetles?

  23. Chris Davis, I would have like to see that! Any pictures of your femur-equipped test rig?

  24. Chris, I also agree that that is DAMN COOL. I would love a picture, esp if you have a paper to go with it! I’ll blog it!
    Coturnix: good idea. Perhaps I shall issue a call for stories, though we all know a bunch of anecdotes aren’t data. Perhaps a survey?

  25. But, will the beetles do the survey?

  26. Only one breakage – might have been low lube, but it pretty much tore the front out and the whole thing rolled up like a sleeve. There was an audible pop which sent me leaping like I’d touched hot lava as realization hit, and she commented that she’d thought all of the stories about “the condom broke” were lame excuses or somebody trying to brag.

  27. I am an engineer. I think this article is confusing and I wonder if the authors were engineers. Quite a number of people report failure of condoms on penetration (insertion). I think they have overlooked another probable reason: It could be condom breakage on penetration is caused by tip (or reservoir) of the condom folding on one side of the condom and trapping air or fluid resulting in the thing popping as the penis is penetrating.

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