Patient education: Barrier and pericoital methods of birth control (The Basics)

What are barrier methods of birth control? — 

For a person to get pregnant through sex, an egg must be fertilized by a partner's sperm (figure 1). "Barrier" methods of birth control prevent pregnancy by keeping sperm from getting to an egg. Condoms are the most commonly used type.

"Pericoital birth control" means any birth control used during sex. This includes condoms as well as other methods like diaphragms, sponges, and spermicides.

What are the different types of birth control used at the time of sex? — 

They include:

●Condoms – There are 2 types:

•External (male) condoms – These are placed over the erect penis before sex. They prevent semen (the fluid that contains sperm) from getting into the partner's body during sex (figure 2).

•Internal (female) condoms – These work in a similar way, but are worn inside the vagina to keep semen from entering the body (picture 1 and figure 3). Internal condoms can be inserted up to 8 hours before sex.

Some people use condoms in addition to another type of birth control, such as the pill. Condoms are the only form of birth control that can also protect against infections you can get through sex. These are called sexually transmitted infections ("STIs"). To protect against STIs, you should:

•Use condoms made out of latex and polyurethane if you do not know your partner's sexual history or if you or a partner already has an STI. Condoms made out of "natural materials," such as sheep intestine, do not protect against STIs.

•Use a new condom for each sex act (vaginal, anal, or oral sex).

Do not use an external and internal condom at the same time. Using them together makes it very likely that 1 or both will break.

●Diaphragm and cervical cap – A diaphragm is a flexible device inserted through the vagina and placed over the cervix before sex (picture 2). It is used along with foam, gel, or cream that contains spermicide, which kills sperm. The diaphragm keeps the spermicide in place around the cervix. If sperm cannot travel through the cervix, they cannot fertilize an egg.

A cervical cap is similar to a diaphragm, but smaller. It is usually not recommended for people who have given birth before. This is because pregnancy and childbirth change the size of the cervix, which makes a cervical cap fit less well.

●Sponge – The birth control sponge is a soft, disk-shaped device that contains spermicide. It is inserted through the vagina before sex. It works by preventing sperm from getting into the uterus.

●Spermicides – These are chemicals that kill sperm. They come in different forms, including foams, gels, creams, films, and tablets. Spermicide can be used by itself, but works better if used with another method such as a condom or diaphragm.

●Vaginal "pH regulator" gel – This is inserted into the vagina like spermicide, but works in a different way. Instead of killing sperm, it changes the level of acid in the vagina, which makes sperm unable to move. It is less likely than spermicide to irritate the vagina or the partner's penis.

Vaginal pH regular gel can be used with another method such as a condom or diaphragm. It should not be used with a type of birth control called the "vaginal ring," which contains hormones.

Before using any of these types of birth control, make sure it is not expired.

How well do these methods of birth control work? — 

It depends on which type you use. The table shows the average chances of pregnancy for people who use each type (table 1). In general, barrier and pericoital methods do not prevent pregnancy as well as some of the other available methods. Other methods include:

●Long-acting methods, such as intrauterine devices ("IUDs") and implants – These can prevent pregnancy for years at a time. Some IUDs, as well as the implant, use hormones to prevent pregnancy.

●Hormonal methods, such as pills, injections, patches, and vaginal rings– These use hormones to prevent pregnancy.

Barrier and pericoital methods of birth control work best if they are used correctly. This means using your method of birth control every time you have sex. Follow the instructions about how and when to use your birth control.

Combining more than 1 type of birth control further lowers the risk of pregnancy. For example, using spermicide along with a condom is more effective than using spermicide alone.

What are the benefits of these methods of birth control? — 

In general, these methods have the following benefits:

●They are safe.

●They do not contain hormones.

●They do not affect your monthly period.

●Many can be bought without a prescription, and some (like condoms) might be free at some health centers.

●They do not affect fertility after you stop using them, so if you or your partner want to get pregnant, you can start trying right away.

●Condoms also protect against STIs.

What are the downsides of these methods? — 

Possible downsides include:

●They do not work as well as other birth control methods to prevent pregnancy.

●You must remember to use them correctly every time you have sex.

●Some methods, like spermicide, can cause irritation of the vagina or penis.

●Some people do not like how sex feels with a condom.

How do I choose the right birth control method for me? — 

This is a personal decision. Think about what is most important to you. You should also think about how likely you are to use each method the right way. For example, can you remember to use your birth control every time you have sex? Do you also want protection from STIs? Are you planning to try to get pregnant in the near future?

Your doctor or nurse can also talk to you about the different options and help you make the best decision for you.

What if I forget to use my birth control? — 

If you have sex and forget to use your birth control, you can take emergency contraception to reduce your risk of pregnancy. Some forms require a prescription, but you can buy others in a pharmacy. If you need to use emergency contraception, do it as soon as possible after sex.

If you are worried you could have an STI, talk to your doctor or nurse. They can tell you about your risk and your options for testing or treatment.

More on this topic

Patient education: Choosing birth control (The Basics)
Patient education: Hormonal birth control (The Basics)
Patient education: Long-acting methods of birth control (The Basics)
Patient education: Emergency contraception (The Basics)
Patient education: Sexually transmitted infections (The Basics)

Patient education: Barrier and pericoital methods of birth control (Beyond the Basics)
Patient education: Birth control; which method is right for me? (Beyond the Basics)
Patient education: Hormonal methods of birth control (Beyond the Basics)
Patient education: Long-acting methods of birth control (Beyond the Basics)
Patient education: Emergency contraception (Beyond the Basics)