Narrow Results

A 26-year-old woman complains of not experiencing a menstruation for nine months.

• What is the definition of secondary amenorrhea?
• What conditions may cause secondary amenorrhea?
• What are the initial investigations?

Secondary amenorrhea is defined as cessation of menstruation, not due to pregnancy, for either (i) a duration of six or more months following regular menstruation previously, or (ii) for a duration of 12 or more months following oligomenorrhea previously.

The commonest causes of secondary amenorrhea are physiological conditions of pregnancy and lactation. Lactating women have infrequent and erratic ovulation. Amenorrhea may persist for as long as a woman remains lactating. Some women, after an average duration of six months of lactation, resume menstruation.

The prevalence of secondary amenorrhea as defined above is 3% overall, 3–5% among college students, 5–60% among endurance athletes, and 19–44% among ballet dancers.

A 45-year-old married woman with two children complains of irregular menstruations for the past three months.

• What specific menstrual history would be informative?
• What conditions may explain her symptom?

Irregular menstruation is one of the most imprecise symptoms in gynecology. An examination of the patient's menstrual calendar is the only way to establish the symptom correctly. It is important to establish if there is a recognizable menstrual flow with normal characteristics in term of the quantity, quality and duration of blood loss. The cycle length can be determined by calculating the interval duration between the dates of onset of each bleeding. This allows irregular bleeding to be classified into one of the following patterns:

• Cyclic bleeding with variable cycle intervals
• Menstrual cycle interrupted by intermenstrual bleeding
• Menstruation complicated by premenstrual bleeding
• Menstruation associated with postmenstrual bleeding
• Erratic bleeding with no cyclic pattern
• Post-coital bleeding, and
• Post-menopausal bleeding.