Sponge... worthy as form of contraception?

Dear Alice,

In exploring other forms of contraception, what is the reliability rate of the "sponge"?

— Spongey

Dear Spongey,

Thanks for stopping by the site as you make your way through your contraceptive information expedition. To answer your question, the contraceptive sponge is 91 percent effective at preventing unintended pregnancy if used correctly and consistently by people who have never given birth. If use isn't correct or used inconsistently, effectiveness is estimated at 88 percent (more on the difference between the two rates in a bit). People who have previously given birth experience lower rates of effectiveness with the sponge, around 80 percent with perfect use and 73 to 76 percent with imperfect use. This round, polyurethane sponge is about two-and-a-quarter inches across and three-quarters of an inch thick with an indentation or "dimple" in the center. This method of birth control is used by inserting it into the vagina to cover the cervix before sex. Upon insertion, it acts as a physical barrier over the cervix so sperm can’t move from the vagina into the uterus to fertilize an egg, and it also contains spermicide (nonoxynol-9), which is a chemical that impedes sperm movement. Seems simple enough, right? Before concluding your information-gathering journey, you might also want to learn more about factors influencing effectiveness and the pros and cons of use.

As far as effectiveness is concerned, correct use of the contraceptive sponge means a number of things:

  • The sponge is thoroughly wet with clean tap water to activate the spermicide.
  • It's squeezed several times until it becomes sudsy (it needs to be sudsy during insertion).
  • It's inserted as far back into the vagina as fingers will allow, with the dimple directly on the opening of the cervix (facing towards the stomach) and the loop on the back (facing towards the spine).
  • The sponge completely covers the cervix (this can be checked by tracing the edge of the sponge with a finger).
  • The sponge is left in place for at least six hours after sex.

Some errors that could compromise the effectiveness of the sponge include not wetting the sponge well enough or squeezing it dry before insertion, removing the sponge too soon, not inserting the sponge until after penetrative sex has already begun, and not using the sponge every time a person has sex. The sponge is also less effective for people who have previously given birth since that experience stretches the vagina and cervix. This results in a poorer fit between the sponge and the cervix and making it easier for sperm to get through. Additionally, the sponge can’t be safely used during menstrual bleeding, so people who have period sex might want to consider alternative contraceptive options during that time. Sponges are disposable and are only intended for one-time use. 

In choosing a form of contraception, the effectiveness rate isn’t the only factor to consider. For example, some of the advantages of the sponge include:

  • Is hormone-free.
  • Allows for spontaneous sex since it can be inserted up to 24 hours before.
  • Can be used for multiple rounds of sex within a 24-hour period without any decrease in safety or effectiveness.
  • Doesn't need to be fitted by a health care provider — it’s one-size-fits-all!
  • Is available over-the-counter (OTC) — no prescription necessary.
  • Isn't as messy as other contraceptive methods that use spermicidal creams, foams, or gels (though it may be messier than other non-spermicidal methods such as condoms or oral contraceptive pills).
  • Is instantly reversible — if users decide they no longer want protection from pregnancy, they can simply take out the sponge and be immediately fertile again.
  • Is usually unnoticed by either partner (and even those who can feel it don’t usually mind since the sponge feels soft and squishy, similar to the vagina itself).
  • Is easy to use with practice.

Though there are a number of pros associated with the use of the sponge, it does have its disadvantages:

  • It can't be used when experiencing vaginal bleeding, including during periods.
  • It can be less effective than hormonal birth control methods, particularly for people who have previously given birth.
  • It doesn’t protect against sexually transmitted infections (STIs), and in fact may make them more common (more on that next).
  • Spermicide (nonoxynol-9) may result in vaginal irritation for some users; this may even increase the risk for infections such as urinary tract infections (UTIs), HIV transmission, and other STIs since it’s easier for bacteria and viruses to enter the body through irritated and inflamed tissue.
  • It may also increase the risk for toxic shock syndrome (TSS), a very rare but potentially deadly infection.
  • Some people may find the sponge difficult to insert or remove, particularly those who aren’t comfortable inserting their fingers into the vagina.

Information gathering is certainly helpful as you determine which birth control method might be good for you. You may also find it helpful to speak with a health care provider about your contraceptive quest, as they will be able to offer guidance on the safest and most appropriate methods based on your wants, needs, and personal health history.

Three cheers for soaking up some birth control knowledge!

Last updated Apr 08, 2022
Originally published Apr 09, 1999

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