HOW DO pH INDICATORS WORK? pH indicators detect the presence of H+ and OH-. They do this by reacting with H+ and OH-: they are themselves. weak acids and bases. If an indicator is a weak acid and is coloured and its conjugate base has a different. colour, deprotonation causes a colour change.
Have varicose veins, which are a common cause of superficial thrombophlebitis. Have a pacemaker or have a thin, flexible tube (catheter) in a central vein, for treatment of a medical condition, which may irritate the blood vessel wall and decrease blood flow. Are pregnant or have just given birth.
Menstrual Cramps Causes. Primary dysmenorrhea (painful menstruation) occurs in the absence of any anatomic abnormalities or causes for the pain. This type of painful menstruation is most often seen in young women in the years following the onset of menstruation. Secondary dysmenorrhea refers to painful menstrual cramps that occur as the result of another medical condition such as endometriosis.