Final answer:
Sexually transmitted infections (STIs) caused by Neisseria gonorrhoeae and Chlamydia trachomatis are the most common cause of pelvic inflammatory disease (PID), which is an infection of the female reproductive organs. Symptoms of PID can include pain in the lower abdomen, vaginal discharge, fever, and painful urination.
Step-by-step explanation:
The most common cause of pelvic inflammatory disease (PID) is sexually transmitted infections (STIs), specifically the bacterial pathogens Neisseria gonorrhoeae and Chlamydia trachomatis. These pathogens can lead to inflammation and infection in the female reproductive organs, including the uterus, cervix, fallopian tubes, and ovaries.
PID can occur when these bacteria enter the reproductive tract through sexual contact and cause an infection. Inflammation of the fallopian tubes, called salpingitis, is the most serious form of PID and can lead to long-term complications like infertility and ectopic pregnancy.