A chemical formula that indicates the simplest numerical ratio of the elements within a molecule, without demonstrating the molecule's chemical bonds or structure. For example, the empirical formula for water is H2O. Synonym: molecular formula.
Pelvic inflammatory disease (PID) is an infection caused by bacteria. When bacteria from the vagina or cervix travel to your womb, fallopian tubes, or ovaries they can cause an infection. Most of the time, PID is caused by bacteria from chlamydia and gonorrhea. These are sexually transmitted infections (STIs). Having unprotected sex with someone who has an STI can cause PID.
Causes of pelvic inflammatory disease. Pelvic inflammatory disease (PID) is caused by an infection developing in the female upper genital tract. In most cases, the condition is caused by a bacterial infection spreading from the vagina or cervix (entrance to the womb) into the womb, fallopian tubes and ovaries. PID is often caused by more than one type of bacterium and it can sometimes be difficult for doctors to pinpoint which are responsible.