The K Health Guide to Safe Sex: STI and Pregnancy Prevention

By Jennifer Nadel, MD
Medically reviewed checkmarkMedically reviewed
April 2, 2021

If you’ve been diagnosed with a sexually transmitted infection (STI), it can be scary, and some may feel stigmatized. However, STIs are incredibly common–in fact they’re the most commonly reported type of infection in the United States.

The Centers for Disease Control and Prevention (CDC) estimates that half of sexually active people under the age of 25 have at least one STI in their lifetime. While young adults under the age of 25 account for about half of the roughly 20 million new cases of STIs in America each year, anyone who is sexually active can contract an STI.

Thankfully, there are effective treatments for many STIs, especially if diagnosed early. Here, we’ll discuss how to protect yourself from STIs while being sexually active. We’ll also cover STI testing, how to have potentially difficult conversations about STIs, and what to do if you engage in an activity that puts you at risk for STI.

Safe Sex Guidelines

There are many definitions of safe sex. Some define it as sexual contact in which bodily fluids like blood, semen, or vaginal fluids are not exchanged. Others define it as sexual contact between two monogamous partners who have each been tested for STIs and each have none. A more general understanding of safe sex is sex using a barrier method of protection against STIs and unplanned pregnancy. Some sexual health professionals prefer the term “safer sex,” to “safe sex,” as all sex carries some risk, whether it be of infection and/or pregnancy, even if precautions are taken. While there is no guaranteed way to avoid STIs without abstaining from sexual contact, here are some guidelines for safer sex that offer the most protection against STIs and unwanted pregnancy.

  • Get tested with any new partner(s) before having sex with them and discuss their past partners, history of STIs, and drug use.
  • Use male or female latex or polyurethane condoms correctly every time you have sex. However, keep in mind that some STIs, like herpes or trichomoniasis, are contagious through genital areas not covered by a condom, like the base of the penis, some parts of the vagina, or the pubis, so while condoms dramatically reduce the chance of contracting an STI, they do not offer 100% protection.
  • Use dental dams or male or female condoms for oral sex, and latex gloves for manual stimulation.
  • Use condoms on shared vibrators and other penetrative sex toys.
  • Avoid sex when under the influence of alcohol or drugs.
  • Avoid sex with someone who is showing signs of an STI like oral or genital sores, blisters, rashes, or unusual discharge.
  • Get tested regularly for STIs if you have multiple or new sex partners. Some STIs cause no symptoms but can still cause damage to organs or fertility.
  • Sexually active women should get regular Pap smears and pelvic exams from a health care provider. While a Pap smear won’t screen for an STI, it can show changes in the cervix which can be associated with HPV.

You can also try sexual activities that do not involve the exchange of body fluids or contact of mucous membranes. These include:

  • Cuddling
  • Massage
  • Masturbation and mutual masturbation
  • Ejaculating on unbroken skin

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Safe Sex Myths

There are some myths about safe sex that can harm your ability to make good decisions about your health. Some include:

  • Douching after intercourse can prevent STIs in women: This is not only untrue, but douching after intercourse can actually increase your chances of STI infection by damaging mucous membranes and pushing fluids containing bacteria and viruses farther into the reproductive tract. Douching also can wash away spermicidal protection, leaving a woman more vulnerable to unplanned pregnancy.
  • Lesbians don’t get STIs: Anyone who exchanges bodily fluids or has mucous membrane contact can contract an STI.
  • Taking birth control means I’m having safe sex: While the pill and other hormonal birth control methods help to guard against unplanned pregnancy, they do not protect either party from STIs.
  • Condoms ruin the mood: Having an STI ruins the mood more! Some condoms can actually increase pleasure by adding extra lubrication, textures, and even heat to a sexual experience. You can also make putting on a condom part of foreplay. If buying condoms in a public place like a grocery or convenience store feels embarrassing, try ordering them from reputable sources online, or grabbing a handful from a community health care center, at a school health care center, or a Planned Parenthood.
  • Topical microbicides and spermicides protect against STIs: Some believe that spermicides containing N-9 can kill STIs upon contact, but this is inaccurate, and some research shows that spermicides containing N-9 might actually increase your risk of HIV infection. N-9 use has also been associated with an increased risk for bacterial urinary tract infections in women, and has not shown to be more effective for preventing STIs or pregnancy than condoms without it.

High-Risk Sexual Activities

Having sex with more than one person, or with someone who has multiple partners increases your risk of getting a STI. Other sexual activities that increase your chances of contracting an STI include:

  • Having sex without a male or female condom.
  • Using the “withdrawal method” (withdrawing the penis from the vagina or anus before ejaculation) instead of condoms to prevent pregnancy and STIs. Pre-ejaculatory fluid can contain sperm, and both pre-ejaculatory fluid and vaginal fluid can transmit STIs.
  • Re-using condoms.
  • Using a condom past its use-by date.
  • Continuing to have sex if a condom has broken or fallen off.
  • Having sex while under the influence of drugs or alcohol to the point where you can’t make decisions based on sound judgment.
  • Having unprotected sex “just this time.” You can get pregnant or infected with an STI with just one instance of unprotected sex!

Methods of Protection

Condoms offer the best protection against STIs, since they act as a physical barrier against the exchange of bodily fluids between partners. Condoms may not protect against every STI, like pubic lice, scabies, or genital warts, and herpes, if the affected areas are outside of the condom, like the pubic mound, testicles, and other genital skin areas. However, condoms still are the best choice for STI protection. When used correctly, female condoms have a 95% rate of effectiveness in protecting against STIs and pregnancy, and male condoms have a 98% rate of effectiveness.

Male condoms

When used consistently and correctly every time, male latex condoms are highly effective in preventing STIs. Condoms can slip off or break, but if used properly these occurrences are fairly uncommon. According to the CDC and the National Center for Biotechnology Information, for every 100 condoms used for vaginal intercourse, approximately two break or slip. Some studies show that rates of breakage and slippage may be slightly higher during anal intercourse. Make sure to check the expiration date on the box or on the individual condoms as expired condoms, or those used over five years after their manufacture date, are not reliable. You can find instructions for putting on a condom here.

If either partner has a latex allergy, male condoms made of polyurethane offer comparable protection against STIs and pregnancy. However, it’s important to note, natural membrane condoms, sometimes called lambskin, are not effective for prevention of STIs.

Some safer sex tips for male condom use include:

  • Use a new condom with each sex act. Do not reuse.
  • Avoid tearing or damaging condom with fingernails, teeth, and when opening the package or putting it on.
  • Put on the condom after the penis is erect, and before any genital, oral, or anal contact with your partner.
  • Make sure there’s enough lubrication during vaginal and anal sex, as an overly dry environment can make condoms more apt to break.
  • Use only water-based lubricants (like K-Y Jelly, Astroglide, and glycerin) with latex condoms, as oil-based lubricants (petroleum jelly, massage and mineral oils, body lotion) can damage latex.
  • To prevent slippage, when withdrawing the penis with a condom, hold the condom against the base of the penis while the penis is still erect.
  • Store condoms away from excessive heat in a cool, dry place.

Female condoms

Female condoms are pre-lubricated polyurethane condoms that fit inside the vagina. Unlike male condoms, they don’t come in different sizes, and are sold as “one size fits all.” While female condoms can be more expensive than male condoms, you may be able to get them covered by your health insurance if your health provider prescribes them to you. They have the benefit of not requiring immediate withdrawal after sex, and you can insert them up to eight hours before use. For those who want a female-controlled protection method, they’re a great choice. You can see how to insert a female condom here.

Tips for effective female condom use are similar to those for male condom use. They include:

  • Use a female condom from start to finish, every time you have vaginal sex, and use a new condom with each sex act. Do not reuse them.
  • Do not use after the expiration date.
  • Be careful not to tear or damage the condom when removing it from the package and while inserting.
  • While female condoms come pre-lubricated, you can use additional lubrication if needed to help prevent slipping and tearing. Female condoms can be used with any kind of lubricant–oil or water-based.
  • Store them away from excessive heat in a cool, dry place.
  • Don’t use a female condom with a male condom, as they can catch on each other and tear.
  • Female condoms are not approved for preventing STIs during anal sex.

Contraceptive Methods Effective Against Pregnancy but Not STIs


Diaphragms should not be used to protect against STIs. While some studies show that cervical diaphragms may offer some protection against cervical gonorrhea, chlamydia, and trichomoniasis they do not protect against other STIs like HIV or herpes, and are less effective than condoms in preventing pregnancy.

Non-barrier contraception

Contraceptive methods that are not mechanical barriers, like oral contraceptives, the patch, the pill, the ring, implants, injectables, intrauterine devices (IUDs), surgical sterilization, and hysterectomy offer protection against pregnancy but not STIs.

How to Get Tested for STIs

You can get tested for STIs at your doctor’s office, a community health clinic, the health department of your school, or your local Planned Parenthood health center. Most health insurance covers STI testing, and if you’re uninsured many health care services will provide it for free or at a reduced cost. You can find out which STI tests you need, and where to get them, at this CDC page.

How to Talk to Your Partner About Getting Testing

Broaching the subject of getting tested for STIs or sharing the results of an STI test can understandably cause some people distress. While it’s very natural to feel nervous or awkward, the conversations are important for your health and the health of your partner or partners. Here are some tips on how to have the conversation:

  • The best time to talk to a new partner about getting tested is before you have sex with them. Getting tested, and waiting to find out your results, with a new partner before having sex with them is one of the best ways to prevent STIs. You can use the waiting time for getting tested and receiving results to build exciting sexual tension, talk about what you like and don’t like, and fantasize and share about how you’d like to have sex.
  • Choose a time to talk when you can be in a calm environment conducive to a thoughtful and safe conversation. It should be in a place where you won’t be interrupted. If you’re really nervous, you can practice what you’re going to say with a friend, or even aloud to a mirror. Sometimes rehearsing, or writing your main points down, can help you feel more confident and prepared.
  • If you feel uncomfortable bringing up the topic, you can start by saying something like, “I feel weird talking about this, but…” or, “I want us to be honest with each other, so I was thinking we could talk about sexual partners in the past and STIs.” If a more casual approach suits you better, you can simply present the facts with something like, “I’d like to get tested for STIs since we’re new partners. Want to come with me to get STI tests together on Sunday?”
  • Assure them that your desire to get tested is not because you don’t trust them. Many people have an STI, some for years, without knowing it. You can let them know that your desire to be tested, and have them tested, is because you value both of your health.

What to Do If You Have Unprotected Sex

Many sexually active people have unprotected sex at some point due to birth control failing, heat-of-the-moment decisions, peer pressure, or other factors out of their control such as sexual assault. If you have had unprotected sex, here are some things you can do to minimize the potential consequences:

  • Avoid vaginal or rectal douching: Some believe that douching after intercourse will wash out the bacteria and viruses that cause STIs, but the opposite is actually true. Douching can actually increase your chances of STI infection by damaging mucous membranes and pushing fluids containing bacteria and viruses farther into the reproductive tract. Douching also can wash away spermicidal protection, leaving a woman more vulnerable to unplanned pregnancy.
  • To prevent pregnancy, take an emergency contraceptive pill: They work best if taken within 72 hours of unprotected sex. This will not protect you from STIs but it can significantly reduce your chances of pregnancy. You can likely find emergency contraceptive pills at your pharmacy or at Planned Parenthood. Not all stores carry emergency contraception so it is best to call ahead to check if it’s available.
  • Make an appointment to be tested for STIs: If you contract an STI through unprotected sex, it’s best to know about it as soon as you can. Prompt treatment can mean less or no long-term health consequences.
  • If you think you might have been exposed to HIV, consider taking post-exposure prophylaxis (PEP): PEP should be started within 72 hours after a possible exposure to HIV, so if you think you might have been exposed during unprotected sex, make an appointment with a health care provider or go to the emergency department right away.

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K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Jennifer Nadel, MD

Dr. Jennifer Nadel is a board certified emergency medicine physician and received her medical degree from the George Washington University School of Medicine. She has worked in varied practice environments, including academic urban level-one trauma centers, community hospital emergency departments, skilled nursing facilities, telemedicine, EMS medical control, and flight medicine.