Menstrual Cramps

• "Stomach pain" during menstrual periods often refers to menstrual cramps. Cramps are caused by shedding of the uterine lining that results in menstrual bleeding. Over-the-counter pain medication is usually enough to relieve menstrual cramps.
  
  

Nausea and Vomiting

• Some women experience nausea and vomiting as a result of menstrual cramps. Stomach pain resulting from nausea and vomiting can be relieved with over-the-counter medication for upset stomach, such as Pepto-Bismol.
  
  

Endometriosis

• Women who suffer from endometriosis often have severe cramps, abdominal pain, and nausea, vomiting and diarrhea during menstruation.
  
  

Uterine Fibroids

• Rarely, uterine fibroids will result in stomach pain during menstruation. Uterine fibroids are noncancerous tumors that grow on the uterine walls.
  
  

Pelvic Inflammatory Disease

• Pelvic inflammatory disease (PID), an infection of the female reproductive system that can be transmitted sexually, has been associated with painful periods.
  
  

When to See a Doctor

• If you experience severe menstrual pain that is unusual, new, or interferes with your daily activities, you should consult a physician.