Only 5%-30% of women who have a lab test that confirms they have chlamydia develop symptoms of the disease. About 30% of these women develop serious complications such as damage to the fallopian tubes (the tubes that connect the ovaries to the uterus). This damage is caused by pelvic inflammatory disease and may result in infertility. Damage to the fallopian tubes can also increase the risk of ectopic pregnancy (when the fertilized egg implants outside of the uterus). Untreated chlamydia in pregnancy may result in premature birth.