STIs you can have with no symptoms

If you’re sexually active, getting a sexually transmitted infection (STI) is a real possibility. 
The Centers for Disease Control (CDC) estimates that 20 million new STI infections occur each year in the U.S. That's why it's so important to get tested regularly, and to be honest with your doctor and any new partners about your sexual activity. It's even more important when you consider that condoms can't protect against all STIs and that STIs with no symptoms exist—some of which can do serious damage if they go untreated.
Some STIs, like HIV and syphilis, are typically known for being symptomatic, so an infected person will show signs of infection. But there are a few out there that are actually known for being asymptomatic, which means you wouldn’t know you have the STI until it’s spread or led to other side effects. According to the CDC, 24,000 women become infertile each year because of an undiagnosed STI.
Here are the STIs you should be aware of that don’t have obvious symptoms:
Human papillomavirus (HPV)
HPV is the most common sexually transmitted infection and one that condoms can’t always protect against. There’s a chance you’ll have HPV at some point in your life – whether or not your realize it. Some strains can cause genital warts, but many don’t show any physical signs at all. 
While it’s likely you’ll have the virus at some point in your life and nothing bad will come of it, some strains of HPV can cause cervical cancer. Getting a regular Pap smear is important because an abnormal Pap smear indicates changes in the cervical cells usually caused by HPV. Depending on the type of abnormal cells found, you may be tested to confirm HPV is the cause. 
Chlamydia is one of the most common STIs in women under 25 and is known as a “silent” infection, since most people never experience symptoms. Symptoms of chlamydia include abnormal vaginal discharge or a burning sensation during urination several weeks after sex with an infected partner. It can be easy to confuse these symptoms with something like a yeast infection, so it’s important to see your ob/gyn if you notice changes in discharge, pain or burnin. But, again, it could have no symptoms at all. 
If chlamydia goes untreated, it can spread to the uterus and fallopian tubes, resulting in pelvic inflammatory disease. Pelvic inflammatory disease can cause scarring in the fallopian tubes, which can lead to permanent damage that causes infertility. Scarring can also cause an ectopic pregnancy, which can be life-threatening for both mom and baby.
The CDC recommends annual chlamydia screenings for women under 25, pregnant women, or anyone with a new sexual partner (or if you’re not sure of your partner’s STI status). If found early, chlamydia can be treated with antibiotics.
Similar to chlamydia, gonorrhea is most common in sexually active women under 25 and the majority will never experience symptoms. While the two are different infections, chlamydia and gonorrhea are commonly diagnosed together. Mild symptoms for both are similar (if they ever show up).
If gonorrhea goes untreated, it can lead to pelvic inflammatory disease, scarring and damage to reproductive organs. Your risk of getting HIV is higher, as is your chance of getting life-threatening infections in other parts of your body. Gonorrhea during pregnancy can cause premature birth, miscarriage, low birth weight and serious health complications for newborns.
The CDC recommends an annual gonorrhea screening for women under 25, pregnant women, or anyone with a new sexual partner (or if you’re not sure of your partner’s STI status). Like chlamydia, gonorrhea can be treated with antibiotics. 
Herpes is a viral infection that can present on your mouth or genitals. According to the CDC, one out of every six people between 14 and 49 years old in the U.S. has genital herpes. While most people think of herpes as painful, red blisters, not everyone gets those. While herpes is most infectious during an active breakout, it can still be spread when no symptoms are present. 
The best way to reduce your risk of herpes is to use barrier methods (like condoms, dental dams) correctly every time you have sex. While there’s no cure for herpes, there is treatment to manage the symptoms. If you believe you’ve been exposed to herpes, talk to your doctor so they can do a swab test of symptoms or a blood test. If you have it, your doctor will prescribe medication to manage symptoms and talk with you about reducing the risk of transmission to sexual partners.
This STI is pretty common and caused by a parasite. According to the CDC, an estimated 3.7 million people have trichomoniasis, but only about 30 percent of people with this STI show symptoms. When symptoms present, they can include: itching, burning, redness, soreness, uncomfortable urination, and vaginal discharge that’s different and comes with a fishy odor. For men, the symptoms could include: itching and irritation, a burning sensation after peeing or ejaculating, and a discharge from the penis. These symptoms can come within five to 28 days of being infected.
If left untreated, trichomoniasis can increase your risk of acquiring other STIs, including HIV. If you’re pregnant, trichomoniasis can cause babies to be born preterm or with a low birth weight. 
Using condoms every time you have sex lowers your risk of getting trichomoniasis, but it’s possible to be infected even if you practice safe sex. Routine trichomoniasis screening isn’t recommended for everyone, but the CDC does recommend screening in certain high-risk areas of the country and in people with a high risk of infection. Trichomoniasis can be cured with antibiotics, but it’s possible to get infected multiple times. 
Michael Cackovic is an ob/gyn at The Ohio State University Wexner Medical Center.