Like the cervical cap, the diaphragm is a physical barrier that blocks the cervix to prevent pregnancy. The device has been used a birth control method in the U.S. since the early 1900s and was widely popular before the introduction of birth control pills.

What Is It?

The diaphragm is a dome-shaped device that is inserted into the vagina to prevent pregnancy. The diaphragm is flexible and made out of latex or rubber.

How Does It Work?

The diaphragm is inserted before intercourse to block sperm from traveling through the cervix during sex. Diaphragms are used in conjunction with spermicide, which helps to stop and kill sperm. If sperm cannot reach the uterus and fallopian tubes to fertilize the egg, pregnancy cannot occur.  

How Do I Use It?

You need a prescription to use a diaphragm. Make an appointment with your doctor to determine if the diaphragm is the best birth control method for you. Your doctor will also help you find a diaphragm size that fits.

You can insert the diaphragm up to six hours before intercourse. Before inserting, apply spermicide on the inside of the cup. Then fold in half with the spermicide on the inside pocket and insert into the vagina as far as it will go. Let go and allow the diaphragm to unfold, making sure the cervix is covered. Do not remove the diaphragm until at least six hours after sex, but do not leave it in for longer than 24 hours. 


The diaphragm is 80 to 91 percent effective in preventing pregnancy, depending on how well it is used. The use of spermicide improves the effectiveness of the diaphragm.


The diaphragm is a convenient birth control choice because it is simple, portable, and easy to insert. Because the diaphragm can be inserted in advance, it does not necessarily interrupt the sexual experience. Many women prefer the diaphragm because, unlike many hormonal birth control options, it does not interfere with the body’s natural hormones.


The diaphragm does not protect you from sexually transmitted disease. It is not the most effective form of birth control, as there is more room for error if the diaphragm slips during intercourse or does not fit right. The diaphragm is slightly less convenient than other barrier methods of birth control because you must have a prescription and medical fitting before use. While there are no serious side effects of using a diaphragm, some women experience irritation, discomfort or infections.