Ask the Doctors: Kegel Balls, Big Toys, and the IUD

I was hoping you could tell me — would using Kegel exercising balls like Smart Balls interfere with my IUD (Mirena)? I don’t want it to get knocked out of place, or have the string fall out or something.

Also, I assume this varies, but how big is too big (of a dildo or penis) for a woman with an IUD?  Will I know it when I feel it? Could it potentially cause damage if it’s too big?

Most sex toy use is fine with an IUD. The biggest possible exception wouldn’t be the Smartballs, anyhow, which are more for tugging down at the vaginal muscles at the vaginal opening, not so much pushing inward toward the cervix, like you might use a dildo. Some doubt has been cast on rotating toys for women with IUDs, though, like the Rabbit (and other similar vibes) and the Sybian, that big, expensive saddle-like toy with a rotating dildo on it.


One factor has to do with the threads on your IUD. The shorter they are, the less of an issue they may be when you’re using toys; your gynecologist can trim them back for you to a length that won’t get in the way (2 cm. to an inch, says one discussion group user, though this of course ought to be decided in consultation with your doc rather than me or Google). You can also curl the filaments around your cervix to get them out of the way. The relevant question with large toys is really whether the girth of the toy, in particular, is great enough to trap the strings against the vaginal wall and create a traction-like pull on them. The shorter they are (or further up past the cervix they’re curled), the smaller the likelihood of this occurring. To shed further light on your size question, I contacted my old pal and colleague Jo-El Schult, who sold lots of toys here at Good Vibrations before she moved on to a job as a Health Educator for Planned Parenthood Shasta-Pacific. “There should be no potential damage if she uses a large dildo,” says Jo-El. “Given that it was placed correctly, the actual device should be very stable in the fundus of the uterus. Do people’s IUC’s come out periodically? Yes. Is it because of vigorous sex? Unlikely.” (IUC, in case you haven’t heard them called this before, stands for “Intrauterine Contraceptive,” and is an alternate usage for “IUD.”)

There’s one issue to think about re: string length that doesn’t have to do with toy use, but rather with partner sex: namely, that there are some men who say they can feel IUD threads during intercourse and that they can be uncomfortable. Likely these are the well-endowed guys (how well-endowed? I don’t know, the Salon letter-writer who clued us in didn’t specify, but he did use the phrase with reference to himself; it’s safe to assume that a man whose penis is long enough to actually or nearly make contact with the cervix would fall into that category, for purposes of this discussion). At least one doctor whose blog I found feels the Mirena’s strings are stiffer than the ParaGard’s (the other commonly-used IUD in the US), which may make a difference. And trimmed threads might, in this case, pose a greater problem for the partner, since they’d be stiff filaments poking out of the os cervix; they wouldn’t wrap around the cervix, if they were that short.

I assume you know how to check the threads on your IUD; this should be part of your monthly care regimen when you’ve had one inserted, for as long as you’re using it. If this isn’t something your gyno showed you how to do when you got it fitted, please get trained in this simple procedure. That way, if you have very vigorous partner sex or an especially rowdy toy session, you can check the strings later that day, after your vaginal engorgement has subsided (and you come down from Cloud 9).

With an IUD, of course, you need to be vigilant to watch out for anything that might promote infection — sex toys and body parts entering your vagina need to be clean, plus use condoms or stay monogamous when it comes to partner sex. It’s very possible to bring home bacterial infections like chlamydia or gonorrhea after having “extracurricular” sex, so it’s important you and your partner understand what’s at stake. I’m guessing this won’t need to be pointed out to you (but I’m going to say it in case other readers aren’t very familiar with IUDs): An IUD does not prevent disease, only pregnancy. If a woman is at any risk of contracting an STD, she’d best use a condom in addition to the intra-uterine device. I’d heard, in fact, that women with IUDs who contract bacterial infections or STDs were at higher risk for dangerous complications, but Jo-El tells me that take on things is just a little outdated: “The Mirena, in particular, is hormonal,” she says, “which causes the cervix to create a mucus plug at the os, making it more difficult for fluids to pass into the uterus. IUC users do not necessarily have greater risk of STD complications. Of course ANYONE who has an untreated STD is at greater risk for complications (pelvic inflammatory disease, sterility, etc.)” than someone who doesn’t have an STD at all.

One last factoid: Information about IUDs also indicates there might be an increased risk of expulsion if you’re nulliparous (that is, you haven’t had a baby); if that’s the case with you, that’s one more reason to check those strings if masturbation or partner sex has gotten especially wild and crazy.

By the way, just as an aside: If you’re a little frustrated that the folks who develop contraceptive devices don’t seem to pay quite enough attention to the way people really have sex — well, that makes two of us.

We’re dedicated to getting you the information you need about sex, pleasure and your health. If you have any questions, please email our staff experts, Dr. Carol Queen and Dr. Charlie Glickman, at! For product-related questions, please email or call our customer service staff at


Dr. Carol Queen

Carol Queen has a PhD in sexology; she calls herself a "cultural sexologist" because her earlier academic degree is in sociology: while she addresses individual issues and couple's sexual concerns, her overarching interest is in cultural issues (gender, shame, access to education, etc.). Queen has worked at Good Vibrations, the woman-founded sexuality company based in San Francisco that turned 35 years old in 2012, since 1990. Her current position is Staff Sexologist and Good Vibrations Historian; her roles include representing the company to the press and the public; overseeing educational programming for staff and others; and scripting/hosting a line of sex education videos, the Pleasure-Ed series, for GV’s sister company Good Releasing. She also curates the company's Antique Vibrator Museum. She is also the founding director of the Center for Sex & Culture, a non-profit sex ed and arts center San Francisco, and is a frequent lecturer at colleges, universities, and community-based organizations. Her dozen books include a Lambda Literary Award winner, PoMoSexuals, and Real Live Nude Girl: Chronicles of Sex-Positive Culture, which are used as texts in some college classes. She blogs at the Good Vibes Magazine and at SFGate's City Brights bloggers page and contributes to the Boston Dig. For more about her at

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