Oligomenorrhea is infrequent menstruation, occurring at intervals >35 days, thus only permitting 4-9 periods per year. Menstrual periods should have been previously established, before the development of infrequent flow.

Patient information

Oligo-menorrhea. What sort of prefix is that?
Do you know what an oligopoly is ? It's like a monopoly, but there's multiple, but only a FEW players, like Coles and Woolies. Similarly, oligomenorrhea means FEW periods. So there's not that much. It's infrequent.

Isn't that amenorrhea?
It's where you don't get a period, at all.

How do you define a few periods?
It's normally 28 days. It's abnormal if it takes longer than 35 days to have a period. With only 365 days in the year, instead of having 13 periods, it reduces down to 10, or even lower.

• Prolactinomas (i.e. adenomas of the anterior pituitary)
• Thyrotoxicosis
• Hormonal changes in perimenopause
• Prader-Willi syndrome
• Grave's disease
• Endurance exercises (e.g. running, swimming, ballet dancing, tennis), with athletic women possibly having even amenorrhea, proportional to the intesntiy of exercise
• Breastfeeding, due to hormones which delay ovulation
• PCOS (polycystic ovary syndrome, where excessive [male] androgens are released by the ovaries), which presents with menstrual abnormalities ranging from amenorrhea to menorrhagia
• Eating disorders, especially anorexia nervosa, but can also be caused by bulimia nervosa

• Duration of such events may vary

• Amenorrhea (total cessation)
• Menorrhagia (unusually heavy)
• PCOS (oligomenorrhea +male pattern changes, OR +polycystic ovaries)