Surprising ways STIs affect the sexes differently

When it comes to certain sexually transmitted infections (STIs), people who are assigned female at birth may experience higher rates or more serious long-term consequences, depending on the condition.

Sangeeta Sinha, MD, an OBGYN at StoneSprings Hospital Center in Dulles, Virginia, discusses sex-differences in STIs, and offers essential facts about prevention.

“Male to female HIV transmission during vaginal sex is more efficient than the other way around,” says Dr. Sinha. “One reason for this is that when a woman has unprotected sex with an HIV positive man, he deposits a considerable amount of semen into her vagina.”

In the opposite case, when an HIV positive woman has sex with a man, far less infected bodily fluid is deposited into his urethra (the tube that allows urine and semen to leave his body), Sinha explains.

The vagina is also:

• Larger in surface area than the penis, so more tissue is exposed
• More likely to tear during sex than the penis, making extra openings for the virus to enter the bloodstream
• Exposed to the virus for a longer time period, since semen stays in the vagina for several days after sex

So, what can you do to lower your risk?

You can reduce your odds of contracting HIV by:

• Wearing condoms during anal, vaginal, and oral sex. Use a dental dam if performing oral sex on a woman. Condoms reduce HIV transmission during vaginal sex by 80 to 90 percent when they are used appropriately.
• Talking to your healthcare provider about pre-exposure prophylaxis (PrEP), a daily medication for people at especially high risk for HIV. When taken consistently, it lowers the risk of getting HIV through sex by over 90 percent. Using condoms along with PrEP offers even more protection.  

You should also get tested for HIV at least once. Get tested again if you’re diagnosed with another STI, you’ve had more than one partner since your last test, or you’ve engaged in high-risk behaviors like anal or unprotected sex outside of your relationship.

Women are less likely than men to show gonorrhea symptoms. That keeps them from getting diagnosed promptly. Untreated gonorrhea can lead to long-term issues like:

• Pelvic inflammatory disease (PID), a condition that can cause severe pain, especially during sex and menstruation, among other symptoms. It can also cause no symptoms at all, increasing the risk for ectopic pregnancy or infertility without warning.
• Ectopic pregnancy, or a painful pregnancy that develops outside the uterus, such as in the fallopian tubes or on an ovary. An ectopic pregnancy isn’t viable and is a major cause of maternal death, especially during the first trimester.
• Infertility

Untreated gonorrhea also increases the chances of catching other serious infections like syphilis and HIV. Make an appointment with your healthcare provider if you suspect you’ve been exposed, or you’re showing gonorrhea symptoms like burning during urination, vaginal discharge, and bleeding between periods.

Untreated STIs cause infertility for at least 24,000 women in the United States annually. “STIs like gonorrhea, chlamydia, herpes, and syphilis can cause severe pelvic infections,” says Sinha. “Infections may travel from the vagina to the cervix, and possibly to the fallopian tubes—even to the ovaries. In some cases, after those infections heal, the fallopian tubes or ovaries form scar tissue, resulting in infertility.”

This is a significant consequence of STIs, she continues, and can be potentially devastating for people. Infertility can contribute to depression and low self-esteem among those who may want to start a family but experience difficulty getting pregnant.

“Unplanned pregnancy is one of the biggest consequences of unprotected sex and it, of course, affects women more than men,” says Sinha. Along with the stress, responsibility, and expenses of pregnancy, STIs can also lead to pregnancy and birth complications, such as:

• Transmitting an infection like HIV to the fetus or herpes to the newborn
• Having a low birth-weight baby, which raises the infant’s risk of infections, developmental delays, and learning disabilities later on
• Stillbirth

All pregnant people should be tested for STIs during their first prenatal visit, according to the CDC. Even if they test positive, prompt treatment can dramatically reduce the chance of transmitting an STI. For example, treatment reduces the odds of an infant contracting HIV to less than 1 in 100.

Vaginal changes can occur with menstruation, menopause, new bath products, and more. Itching or vaginal discharge can also develop due to routine infections like yeast infections. STIs can be dismissed as these routine changes and treated incorrectly with home remedies or over-the-counter medications.

On the other hand, symptoms like penile discharge may be harder to explain away, which may result in earlier treatment seeking. Skin changes are also more immediately visible on a penis than they are on a vagina.

Each healthcare appointment is an opportunity to talk about safe sex and get tested for STIs.

“HIV screening, for example, can now be done in many doctor’s offices,” says Sinha. “It’s a quick blood test, you may be able to get your results right there, and then you’ll know where you stand.”

But don’t assume your healthcare provider will automatically test you for HIV or any other STIs during office visits. Instead, talk about your sexual history and partners so your provider may determine which tests are right for you.

“The bottom line is you need to use protection and know your partner’s history,” says Sinha. “Women often bear the greater burden in terms of birth control—from taking a daily pill, to implants in their arm or uterus, to the costs of those treatments. The least men can do is wear a condom.”

Interested in getting tested for STIs?

• Locate an OBGYN through Sharecare’s Find a Doctor tool.
• Visit FindSTDTest.org, a website from the CDC to find free, confidential testing centers near you.
• Text your ZIP code to KNOW IT (566948) to receive information about local HIV testing sites.