How Common is AUB-C?

Blog Post by Malcolm G. Munro MD, FACOG, FRCS(c), Professor, Department of Obstetrics and Gynecology, David Geffen School of Medicine at UCLA, Director of Gynecologic Services, Kaiser Permanante, Los Angeles Medical Center, Los Angeles, CA, USA

Among the varied causes of the symptom of heavy menstrual bleeding (HMB) in reproductive aged women are congenital disorders of hemostasis, commonly called coagulopathies. In the new FIGO PALM-COEIN classification system for causes of AUB in the reproductive years, such women are categorized as having AUB-C.(1) While there exist a number of such entities, by far, the most common is von Willebrand disease (vWD), a disorder that has a mean prevalence of about 13% in women of all ages with HMB.(2) There exist three recognized variants of vWD; the majority has the mild Type 1 form that can only be diagnosed with certainty using specific testing for von Willebrand factor (vWF). Type 2 vWD is a quantitative deficiency where vWF levels are typically 10-45% of normal while Type 3 is a serious deficiency that adversely impacts hemostasis even in the face mild injury or menses. Other less common factor-based coagulopathies are caused by deficiencies in Factors II, V, VII, VIII, IX, X, XI and XII. Of course, AUB-C can be also caused by iatrogenic means secondary to the use of anticoagulants. Because it is not clear to what degree the mild variants of inherited coagulopathies contribute to symptom of HMB in a given woman it is important to always perform a complete evaluation considering all of the elements in FIGO’s PALM-COEIN classification system.

AUB-C may present initially at menarche, when the adolescent, perhaps for the first time, has to attain satisfactory hemostasis over a large bleeding surface – the endometrium. The problem can be compounded because at menarche, many, if not most, such bleeds are anovulatory, where the endometrium is already deficient in endometrial vasoconstrictors such as PG F2-α and endothelin-1 that are largely dependent on the production of progesterone. When added to the delay in presentation fostered by the embarrassment and immaturity of the typical adolescent, menarcheal girls with von Willebrand disease and other disorders of systemic hemostasis are at great risk for a serious episode of HMB. Indeed, one study has reported that almost 20% of young girls who presented in the emergency department with acute HMB have AUB-C. (3)

So how does one diagnose AUB-C? The first step is to have a high index of suspicion. So when an adolescent presents around menarche with acute HMB, steps should be taken to evaluate for a systemic disorder of hemostasis. For other women, there is evidence that a structured history can identify about 90% of the women with laboratory evidence of von Willebrand disease. Any woman with lifelong heavy menstrual bleeding is at risk, as are those with a family history, or with a personal history of frequent bruising, bleeding with brushing teeth or unexplained bleeding associated with childbirth or surgical procedures.(4, 5) For women who fail the screen, the process should start with non-specific assays including prothrombin time (PT), partial thromboplastin time (PTT), ABO blood type and Ivy bleeding time as well as more specific assays measuring vWF, Ristocetin co-factor and Factor VIII . Other assays such as those for platelet aggregation or more rare factor deficiencies can be obtained as appropriate, depending on the clinical situation, and the advice of a consulting hematologist. Of course, the evaluation of any individual with AUB, including HMB, should be performed considering focal lesions of the lower genital tract as well as the other potential contributors to the bleeding categorized in FIGO’s PALM-COEIN system, two of which (AUB-E and AUB-O) have been discussed in previous editions of this blog.

Treatment of women with AUB-C will vary according to the severity of the disorder, the desires regarding current and future fertility, and the response to simple interventions such as tranexamic acid and local or systemic progestin-containing regimens. More about AUB-C can be found in the book Abnormal Uterine Bleeding, from Cambridge Medical Press.(6)

1. Munro MG, Critchley HO, Broder MS, Fraser IS. FIGO classification system (PALM-COEIN) for causes of abnormal uterine bleeding in nongravid women of reproductive age. Int J Gynaecol Obstet. 2011;113:3-13.
2. Shankar M, Lee CA, Sabin CA, Economides DL, Kadir RA. von Willebrand disease in women with menorrhagia: a systematic review. BJOG. 2004;111:734-40.
3. Claessens EA, Cowell CA. Acute adolescent menorrhagia. American journal of obstetrics and gynecology. 1981;139:277-80.
4. Kadir RA, Economides DL, Sabin CA, Owens D, Lee CA. Frequency of inherited bleeding disorders in women with menorrhagia. Lancet. 1998;351:485-9.
5. Kouides PA, Conard J, Peyvandi F, Lukes A, Kadir R. Hemostasis and menstruation: appropriate investigation for underlying disorders of hemostasis in women with excessive menstrual bleeding. Fertil Steril. 2005;84:1345-51.
6. Munro MG. Abnormal Uterine Bleeding. Cambridge: Cambridge University Press; 2010.

Munro MG. Abnormal Uterine Bleeding. Cambridge: Cambridge University Press; 2010.

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