Because it rarely causes symptoms, people don't know they're infected. So they don't get treated, and they infect their partners, who also don't get treated. Without treatment, the national Centers for Disease Control and Prevention estimates, chlamydia can lead in up to 40 percent of cases to pelvic inflammatory disease, a serious infection of the woman's fallopian tubes that can also damage the ovaries and uterus. It's not known whether chlamydia infection causes fertility problems or other long-term consequences in men. But as far as we know, the biggest price is paid by young women.
Babies sometimes pay a price, as well.
Babies who are exposed to chlamydia in the birth canal during delivery can be born with pneumonia or an eye infection called conjunctivitis, both of which can be dangerous unless treated early with antibiotics. Because so many people are at risk for chlamydia and because the disease can ravage a woman's reproductive system without so much as a symptom, experts recommend regular, widespread screening to detect the disease. Traditional methods of screening require a health professional to collect a swab sample of genital secretions. At worst, it can feel like a tiny menstrual cramp, but most women don't experience any discomfort. Male samples are obtained by inserting a swab into the end of the penis.