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Methods to prevent pregnancy and STIs

Contraception – also known as birth control – is any method used to reduce the chances of unplanned pregnancy. Some forms of contraception also reduce the risk of sexually transmitted infections (STIs). Keep reading to learn about different types of birth control and how they work.

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The different types of birth control

Some forms of contraception act as a physical barrier to prevent sperm from meeting an egg, while others use hormones to prevent pregnancy. To choose the right contraceptive for you, talk to your healthcare provider. You can see your primary care provider or visit your local health department or family planning clinic.

Contraceptives that don’t require a prescription include:

  • Abstinence: This means not engaging in oral, anal or vaginal sex. With abstinence, there is no risk of pregnancy or STIs. It can be hard to maintain. Abstinence provides 100% protection against pregnancy and STIs.
  • External condoms (use every time): An external condom is a barrier method that collects semen and other fluids, preventing them from entering a person’s vagina. It protects against pregnancy and STIs. They’re free at your local health department. Condoms must be used correctly every single time. Condoms break down over time, so pay attention to the expiration date. They’re 98% effective with perfect use and 85% effective with typical use. They’re available over the counter.
  • Internal condoms (use every time): An internal condom is a barrier type of contraception (material much like an external condom) that is inserted into the vagina or anus before sexual intercourse. They can be inserted up to eight hours before sexual contact, help prevent pregnancy and don’t require a prescription. Internal condoms may cause skin irritation around the genitals, you must remember to use them every single time and it only protects against some STIs. With perfect use, they’re 95% effective and 79% effective with typical use.
  • Withdrawal method (use every time): This is the removal of the penis before ejaculation occurs in the vagina. This method is free and more effective when using another birth control method, such as a condom. The cons are you may not be able to withdraw in time, pre-ejaculate may still contain sperm and this method doesn’t offer protection against STIs. With perfect use, it’s 96% effective and with typical use, it’s 78% effective.
  • Spermicide (use every time): Spermicide comes in creams, gels, foams, films and suppositories that have chemicals to stop sperm from reaching an egg to fertilize. It doesn’t protect against STIs, must stay in place for six hours after intercourse and may cause irritation to the genitals. Spermicide is 71% effective when used alone and 97% effective when used with a condom.

Birth control methods that require a prescription include:

  • Pill (take daily): This is a monthly pack of hormonal pills that must be taken once a day. It may help regulate the menstrual cycle and may be free or low-cost. The cons are you must take it at the same time every day, it may cause side effects (like headaches, nausea or weight gain) and doesn’t offer protection against STIs. With typical use, they’re 91% effective. With perfect use, they’re 99.7% effective.
  • Patch (replace weekly): A small patch placed on the body that releases hormones. It must be replaced weekly and you can still shower or swim normally with the patch on. The patch doesn’t protect against STIs and may cause skin irritation. With typical use, it’s 91% effective and with perfect use, it’s 99% effective.
  • Shot (get every 12 weeks): A short with hormones injected into the upper arm or buttocks every 12 weeks. It’s low-maintenance, can be injected at home after the first injection at the doctor’s office, and is effective one week after the first injection. It is usually not recommended for long-term use, doesn’t provide protection against STIs and may cause irregular periods. The effectiveness rate for perfect use is 99%.
  • Vaginal ring (replace monthly): A flexible ring that is inserted into the vagina and releases hormone. It provides nonstop protection against pregnancy if used correctly, may regulate menstrual cycles and reduce cramping, and is low-maintenance. It doesn’t offer protection against STIs and may cause vaginal discomfort, headaches or breast tenderness. It’s 91% effective with typical use and 99% effective with perfect use.
  • IUD (replace every three to 12 years): An intrauterine device is t-shaped and contains copper or progestin (hormone). It is inserted into the uterus by a healthcare provider. It provides long-term protection against pregnancy, is effective immediately and is comfortable. It may cause a slightly higher risk of infection during the first month of use, may fall out or puncture the uterus (rare) and doesn’t provide STI protection. They are more than 99% effective at preventing pregnancy.
  • Implant (replace every three to five years): A small, plastic-like rod is inserted under the skin of the upper arm that releases hormones. The implant provides long-term protection against pregnancy, can shorten or lighten periods and reduce cramps, and is low-maintenance. It may cause irregular periods, nausea headaches or weight gain. IT doesn’t protect against STIs. The implant is more than 99% effective.

Less common methods include:

  • Sponge (use every time): This is a small, round sponge that is made of soft, flexible plastic and contains spermicide. It can be inserted up to 24 hours before intercourse and is easily available. It must stay in place for six hours after intercourse, is less effective for women who have given birth and doesn’t protect against STIs. With typical use, it’s 80% effective and with perfect use, it’s 91% effective.
  • Diaphragm (use every time): A diaphragm is a dome-shaped silicone or latex cup with a flexible rim that’s inserted into the vagina before sexual contact. It can be inserted up to six hours before sexual contact, you can leave it in for up to 24 hours and multiple sexual encounters, and you can reuse it for up to a year. You must leave it in for six hours after intercourse, it may increase the risk of urinary tract infection or toxic shock syndrome, and doesn’t protect against STIs. It’s 88% effective with typical use and 94% effective with perfect use.
  • Cervical cap (use every time): A soft, dome-shaped silicone cup with a firm rim that can be used for up to 48 hours. You can use the same cap for up to a year with proper care between uses and can use it for up 48 hours. The cons are it may increase the risk of urinary tract infection and toxic shock syndrome, it’s less effective after giving birth, and it may move or shift during intercourse. The cap is 86% effective if a woman has never given birth and 71% effective if she has given birth.

Emergency contraception

The emergency contraception pill (sometimes called the “morning-after pill”) can reduce the chance of pregnancy after unprotected sex or if another method of birth control fails. Most options are available over the counter and don’t require a prescription. The pill must be taken within three to five days – the sooner it is taken, the more effective it is.

The copper IUD can also be used if inserted by a medical professional within five days of unprotected sex or birth control failure.

STI Prevention

The following methods are used to prevent STIs:

  • Abstinence
  • Condoms
  • Dental dams: A thin, flexible piece of latex that is placed over the genitals or anus before oral sex. It can easily be made by an unused condom and hard to find in stores.
  • PrEP, which stands for pre-exposure prophylaxis and is prescribed to people who are at risk for contracting HIV. This method only protects against HIV, not other STIs, and is best used with a barrier method. It must be taken daily.

Talk to your healthcare provider about which method is right for you.

Need more info? Ask an Expert.


For more information about staying in charge of your health and future, visit:

A Step Ahead: How to access free LARC methods in Tennessee

Centers for Disease Control and Prevention (CDC)

HHS Office of Population Affairs

Planned Parenthood

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