Particularly when it is caused by chlamydial infection, PID may produce only mild symptoms or no symptoms at all, even while it is seriously damaging the internal reproductive organs. Because of the vague symptoms, PID goes unrecognized both by women and by their health care providers about two thirds of the time. Women who do have symptoms of PID most commonly have lower abdominal pain. Without treatment, PID can cause permanent damage to the female internal reproductive organs. Infection-causing bacteria can silently invade the fallopian tubes, causing normal tissue to turn into scar tissue.
Scar tissue blocks or interrupts the normal movement of eggs into the uterus.
If the fallopian tubes are totally blocked by scar tissue, an egg will not be fertilized by sperm or move to the uterus to develop into a baby. Totally blocked fallopian tubes cause a woman to be infertile. Infertility can also occur if the fallopian tubes are partially blocked or even slightly damaged. About one in five women with PID becomes infertile. If a woman has multiple episodes of PID, her chances of becoming infertile are increased.