Women can experience a variety of menstrual disorders, including:

• Amenorrhea. An absence of menstrual periods. This condition may be further classified as:
  
  
• Primary amenorrhea. The lack of a first menstrual period by the age of 16 years. This condition is also known as “delayed menarche.”
  
  
• Secondary amenorrhea. The absence of menstrual periods in a woman who has previously menstruated regularly. The periods must be absent for at least three months to be considered amenorrhea.
  
  
• Dysmenorrhea. Severely painful menstrual periods. This condition may be further classified as:
  
  
• Primary dysmenorrhea. Painful menstrual periods that are not caused by an underlying disease or condition.
  
  
• Secondary dysmenorrhea. Painful menstrual periods caused by an underlying disease or condition. In some patients, the pain may extend beyond the menstrual period and become chronic (e.g., endometriosis).
  
  
• Hypomenorrhea. Unusually light menstrual periods.
  
  
• Menorrhagia. Unusually heavy or long menstrual periods. Women with menorrhagia may soak through one or more sanitary pads or tampons an hour for several consecutive hours, or have periods that last longer than seven days (or longer than a usual menstrual period). Menorrhagia may be a cause for concern because heavy bleeding can lead to an iron deficiency, and ultimately result in anemia.
  
  
• Metrorrhagia. Menstrual bleeding that occurs at frequent, irregular intervals.
  
  
• Menometrorrhagia. Prolonged menstrual periods that occur at irregular intervals. This condition is a combination of menorrhagia and metrorrhagia.
  
  
• Oligomenorrhea. Unusually infrequent menstrual periods. Woman with oligomenorrhea have fewer than six to eight periods per year.
  
  
• Polymenorrhea. Unusually frequent menstrual periods compared to the normal variation of menstrual cycles.
  
  
• Postmenopausal bleeding. Vaginal bleeding that occurs more than 12 months after the last menstrual cycle.
  
  
• Premenstrual syndrome (PMS).  Physical, emotional and behavioral symptoms that commonly occur in the two weeks prior to menstruation. Some women experience symptoms so severe that they interfere with daily activities. These women may have a severe condition known as premenstrual dysphoric disorder (PMDD), which is diagnosed according to specific criteria established by medical authorities.