Health Library

3 facts you should know about chlamydia

When your doctor asks about your sexual activity, it’s important to be open and honest. Diseases like chlamydia can affect your health—and you might not realize you’re at risk.

3 surprising facts about chlamydia

It's the most common STI (sexually transmitted infection). Chlamydia is caused by bacteria that can infect the uterus and fallopian tubes.
It spreads easily. Chlamydia can spread to a partner through all types of sex—even without ejaculation. And it can spread from pregnant women to their babies.
It rarely causes symptoms. But it can still cause health problems, including infertility.

Should you be tested for chlamydia or other STIs? Take a quick quiz to help you decide.

Reviewed 10/16/2025

Sources:

American College of Obstetricians and Gynecologists. “Chlamydia, Gonorrhea, and Syphilis.” https://www.acog.org/womens-health/faqs/chlamydia-gonorrhea-and-syphilis.
Centers for Disease Control and Prevention. “About Chlamydia.” https://www.cdc.gov/chlamydia/about/index.html.
Office on Women’s Health. “Chlamydia.” https://www.womenshealth.gov/a-z-topics/chlamydia.