abnormal uterine bleeding (AUB)

Last edited 09/2021 and last reviewed 10/2021

Disturbances of menstrual bleeding manifest in a wide range of presentations. Abnormal uterine bleeding (AUB) is an umbrella term used to describe any alteration in the pattern or volume of menstrual blood flow (or any deviation from the normal menstrual cycle) (1)

• in women of child-bearing age this can be a change in menstrual-period frequency or regularity, amount of flow, and duration of flow
• in post menopausal women this usually includes
• vaginal bleeding for 12 months or more after the cessation of menses, or
• unpredictable bleeding in postmenopausal women who are on hormone therapy for 12 months or more (2)

Terminology used for variations in menstrual bleeding is as follows:

• regularity of menstruation – irregular (metrorrhagia), regular, or absent (amenorrhea)
• frequency of menstruation – frequent (polymenorrhea), normal, or infrequent (oligomenorrhea)
• duration of menstrual flow - prolonged, normal, or shortened
• volume of menstrual flow – heavy (menorrhagia), normal, or light
• any additional abnormality should be specified e.g. - intermenstrual bleeding, premenstrual, breakthrough

AUB can be broadly divided into two categories:

• anovulatory bleeding
• presence of irregular or infrequent periods, with flow ranging from light to excessively heavy
• terms commonly associated with anovulatory bleeding include amenorrhea, metrorrhagia, oligomenorrhea
• ovulatory bleeding
• occurs at regular intervals, but with excessive and prolonged duration

Note:

• AUB frequently co-exist with fibroids (although the relationship between the two conditions is not understood completely) (4)

Reference:

• (1) Fraser IS et al. The FIGO recommendations on terminologies and definitions for normal and abnormal uterine bleeding. Semin Reprod Med. 2011;29(5):383-90.    
• (2) Albers JR, Hull SK, Wesley RM. Abnormal uterine bleeding. Am Fam Physician. 2004;69(8):1915-26.
• (3) Singh S et al. Abnormal uterine bleeding in pre-menopausal women. J Obstet Gynaecol Can. 2013;35(5):473-475.    
• (4) Whitaker L, Critchley HOD. Abnormal uterine bleeding. Best Practice & Research Clinical Obstetrics & Gynaecology. 2016;34:54-65.