A contraceptive sponge is a small, round piece of soft polyurethane foam that you place inside the vagina before sex to prevent pregnancy. It works without hormones, is available over the counter, and each sponge is used once and then thrown away. The most widely known brand, the Today Sponge, contains 1,000 mg of a sperm-killing chemical called nonoxynol-9 embedded throughout the foam.
How the Sponge Prevents Pregnancy
The sponge works in three ways at once. First, it physically covers the cervix, creating a soft barrier that blocks sperm from entering the uterus. Second, the spermicide in the foam kills sperm on contact. Third, the foam itself absorbs and traps sperm, reducing the number that could potentially reach an egg. This triple mechanism is what sets it apart from using spermicide alone or a barrier alone.
Before insertion, you wet the sponge with clean water and squeeze it until it becomes sudsy. This activates the spermicide and makes it easier to fold and slide into place. You then push it deep into the vagina with the concave dimple facing the cervix. A fabric loop on the opposite side is used for removal later.
How Effective It Is
The sponge’s effectiveness depends heavily on whether you have previously given birth vaginally. Vaginal delivery permanently changes the shape of the cervix, which makes it harder for the sponge to form a tight seal.
For people who have never given birth, 12 out of 100 will become pregnant in a year of typical use. With perfect use every time, that number drops to about 9 out of 100. For people who have given birth, the numbers are significantly higher: 24 out of 100 with typical use and 20 out of 100 with perfect use. That’s a meaningful gap, and it makes the sponge a much less reliable option for anyone who has delivered a baby.
For comparison, condoms have a typical-use failure rate of about 13%, and hormonal methods like the pill sit around 7%. The sponge is on the less effective end of the birth control spectrum, which is why some people choose to pair it with condoms or another method.
How to Use It
You can insert the sponge up to 24 hours before sex. Once in place, it provides continuous protection for that full window, no matter how many times you have intercourse. You do not need to add more spermicide or replace the sponge between rounds.
After the last time you have sex, the sponge needs to stay in place for at least 6 hours to make sure the spermicide has time to neutralize any remaining sperm. However, you should not leave it in for more than 30 hours total from the time of insertion. Leaving it in longer raises the risk of infection. To remove it, you hook a finger through the fabric loop and pull gently. If the sponge feels stuck or breaks apart during removal, see a healthcare provider to make sure no fragments remain inside.
What the Sponge Does Not Protect Against
The sponge offers no protection against sexually transmitted infections, including HIV. Despite containing a spermicide, nonoxynol-9 has not been shown to prevent STI transmission when used without condoms. A randomized controlled trial among sex workers in Kenya found no protection against HIV from a vaginal sponge containing a high dose of nonoxynol-9. In fact, frequent use of nonoxynol-9 can irritate vaginal tissue, which may actually increase vulnerability to infections. If STI protection matters to you, condoms are still necessary.
Benefits of the Sponge
The sponge appeals to people looking for a hormone-free, on-demand option they can control themselves. You don’t need a prescription or a fitting from a doctor. It’s small enough to carry in a purse, and your partner typically can’t feel it during sex. Unlike a diaphragm, it comes pre-loaded with spermicide, so there’s no extra step of applying gel. And because it’s hormone-free, it won’t cause the side effects associated with pills, patches, or hormonal IUDs, things like mood changes, headaches, or changes to your cycle.
It also gives you the flexibility to be spontaneous. Since you can insert it hours before sex, you don’t have to pause in the moment to deal with contraception.
Risks and Side Effects
The most common complaint is vaginal irritation or dryness caused by the nonoxynol-9. Some people also experience an allergic reaction to the spermicide, which can cause itching, redness, or a burning sensation. If that happens, you’ll want to discontinue use and try a different method.
The more serious (but rare) concern is toxic shock syndrome, a potentially life-threatening bacterial infection. Cases have been reported in sponge users, with symptoms including sudden high fever, low blood pressure, a widespread rash, nausea, vomiting, muscle pain, and vaginal discharge. Keeping the sponge in longer than 30 hours is the primary risk factor. People who have previously had toxic shock syndrome, especially if it was linked to sponge or tampon use, should avoid the sponge. The same caution applies in the weeks after giving birth, when susceptibility to this type of infection is higher.
Who the Sponge Works Best For
The sponge is a reasonable choice for people who want a non-hormonal, no-prescription option and who have never given birth vaginally. It’s particularly practical for people who have sex infrequently and don’t want to commit to a daily pill or a long-term device. Pairing it with condoms significantly improves both pregnancy prevention and STI protection.
It’s a less ideal fit for people who have given birth, given the steep drop in effectiveness. It’s also not the best option for anyone who is sensitive to spermicide or who needs reliable protection on its own, since even with perfect use, the failure rate is higher than most other methods.