Abnormal Uterine Bleeding [AUB]
Abnormal uterine bleeding is a common clinical problem with myriad causes. However, physicians with a solid knowledge of menstrual physiology and a thorough approach to differential diagnosis can evaluate and manage the problem with confidence.
Normal menstrual physiology
The proliferative phase is
characterized by a predominance of estrogen over progesterone and a buildup of
endometrium. The secretory phase begins after ovulation triggers progesterone
production. This phase is marked by a reaction to the combination of estrogen
and progesterone and stabilization in the thickness of the endometrium.
Types and definitions
Causes of AUB
Abnormalities of the
Complications related to
Iatrogenic factors [due to
medicines or medical procedures]
Dysfunctional uterine bleeding - when no other cause can be found. Dysfunctional uterine bleeding is a diagnosis of exclusion. In the vast majority of cases, it is secondary to anovulation [a condition where the follicle does not burst and therefore does not release the egg], which is more common at the extremes of reproductive age ie: teenage girls an women between 40-50 years of age.
Diagnosis of the cause of AUB
Your doctor will ask you a number of questions like:
He will also examine you for signs of thyroid, liver problems etc. A thorough pelvic examination along with a PAP will be done. Pelvic examination may be done under anaesthesia at the time of a scheduled D&C or hysteroscopy etc.
Further tests such as blood counts, pregnancy tests [urine or blood], and an ultrasound are pretty much mandatory. For younger patients this is often enough of a diagnostic work up that may be required as it would be unusual to have cancers at this age. Therefore, women who are under 35 years of age and have no identifiable risk factors for neoplasia [cancer] can be assumed to have dysfunctional uterine bleeding and treated accordingly.
Ultrasound in AUB
Transvaginal USG is much preferred to trans abdominal USG. In TVS [trans vaginal sonography] a probe is placed inside the vagina to evaluate the uterus, ovaries and pelvis. This is much more sensitive and has a better diagnosis rate than trans abdominal USG. USG looks for fibroids, polyps, ovarian tumours as well as the endometrial thickness.
Importance of endometrial thickness [thickness of the lining of the uterus]
Post menopausal patients with an endometrial thickness of more than 4mm and with vaginal bleeding should have a biopsy taken. A post menopausal patient who has a routine screening [without any history of vaginal bleeding] and is found to have an endometrial thickness of 10mm or more should also undergo a biopsy.
However rigid reliance on ultrasound measurement is inadvisable, especially when clinical symptoms suggest pathology.
Currently, there is no accepted cut-off value for premenopausal women with abnormal uterine bleeding that could differentiate normal from abnormal endometrium. This is why age is often used as a criteria - pre menopausal patients above the age of 35 require endometrial sampling.
However any woman over 35 years of age with abnormal uterine bleeding should undergo endometrial evaluation by a D&C combined with a hysteroscopy [hysteroscopy makes the chances of picking up and locating a cause much higher so ideally hysteroscopy & D&C is always to be preferred to a plain D&C].
Treatment of AUB
Treatment of abnormal uterine bleeding varies, depending on the cause. For example if fibroids are found they need to be removed either by myomectomy or hysterectomy, and if cancer is found the appropriate treatment needs to be given.
If no cause is found then the patient is labelled as having dysfunctional uterine bleeding [DUB] and discussion focuses on treatment of dysfunctional uterine bleeding. As previously noted, this is a diagnosis of exclusion. If this type of bleeding is suspected but treatment fails, other causes should be investigated. The goals in treatment of dysfunctional uterine bleeding are to control bleeding, prevent recurrences, and preserve fertility if the patient requires it. The choice of treatment depends on whether bleeding is acute or chronic.
When bleeding is acute, the first step is to determine if the woman's condition is hemodynamically stable [pulse and blood pressure are maintained or not]. A patient with signs of hypovolemia [low BP, high heart rate] should undergo volume resuscitation, be hospitalized and most clinicians proceed to dilation and curettage, which quickly controls bleeding.
The hemodynamically stable patient with acute heavy bleeding should be treated with estrogen. The most convenient method of estrogen administration is use of low-dose oral contraceptives.
After finishing the course of oral contraceptives, the patient typically experiences a heavy, crampy period. She should continue to take low-dose oral contraceptives for at least another 3 months and then undergo reevaluation to determine whether treatment for chronic bleeding is indicated.
Treatment of patients with chronic recurrent bleeding is based on their reproductive desires. Patients who want birth control can use low-dose oral contraceptives. If contraception is not desired, use of cyclic progestins for the first 10 days of each month is the treatment of choice. Patients wishing to become pregnant are candidates for ovulation inducing drugs.
In addition to these measures some patients may be given a trial of drugs such as Mefanamic Acid and Tranexemic Acid which can reduce the bleeding at the time of the periods.
In the cases in which dysfunctional uterine bleeding does not respond to any of the management options described, hysterectomy is an option for those patients who have finished child bearing and are no longer interested in retaining their fertility.
A reasonably common finding on biopsy is endometrial hyperplasia - the treatment of this may be either medical or surgical depending on the degree of hyperplasia, age of the patient and the willingness of the patient to follow up with repeated biopsies or not.