One of the many contraceptive methods in preventing pregnancy would be the use of sponge birth control. It is a vaginal barrier that prevents pregnancy by keeping the sperm from fertilizing an egg inside a woman's ovary produced each month. However, the use of sponge birth control does not protect the user from sexually transmitted diseases that is why a condom should be used as a back-up. The 'sponge' looks like a small, donut-shaped foam that contains Nonoxynol-9, a spermicide ingredient.

Fairly easy to insert, the sponge birth control is placed in the vagina and prevents pregnancy by releasing a spermicide. It works by killing or paralyzing the sperm that comes into the vagina. A ?dimple? on one side of the sponge fits over the cervix to form a barrier to prevent sperm from reaching the egg. This dimple also lessens the chances that the sponge will move out of place during sexual intercourse. Having only one size, the other side of the sponge has a loop for easy removal after use.

The sponge birth control is soft and is not noticeable once inserted. In case it feels uncomfortable, the sponge may removed and re-inserted correctly. If this happens, one needs to gently reposition the sponge deep into one's sexual organ until it covers the cervix, but be careful not to push the fingernail through. Feeling the loop of the sponge is a sign that it is properly inserted. Usually, sponge birth control is available in most drug stores, and does not need a prescription. This costs around $3 each and comes in 3 or 12-piece pack.

The contraceptive sponge may have a decrease in effectiveness once the woman has already given birth. Normally, the sponge birth control method is about 87% effective. This means that in 100 women who use this kind of birth control, 13 women can become pregnant in a year, all with typical use. In addition, the sponge birth control does not protect against STDs. In fact, using spermicides (like the ones contained in the sponge) is not recommended for those women who have multiple daily acts of sexual intercourse.

Allergies from using the contraceptive sponge is rare, but some women can be allergic to the active ingredient of the sponge (spermicide), the preservative, or the polyurethane foam. If in case one experiences any localized itching, burning, redness, rash or irritation, it is better to discontinue the use of the sponge, and call the doctor or gynecologist for more information. It is best to consult with them before using this method of birth control since an allergy to certain drugs can be harmful to one's health. When using this form of birth control, it is best to use it together with a condom, for this will increase the effectiveness in preventing pregnancy, and also lessen the chances of getting an STD. Additional information for using sponge birth control includes the very low risk of getting toxic shock syndrome. It is also not advisable to use during a woman's menstruation, after childbirth, or after a miscarriage.