Abnormal uterine bleeding associated with ovulatory dysfunction (AUB-O) or anovulatory bleeding, is non-cyclic uterine bleeding characterized by irregular, prolonged, and often heavy menstruation. It represents one of the identified causes of abnormal uterine bleeding (AUB), a frequently encountered chief complaint in the primary care setting affecting up to one-third of women of child-bearing age. Though commonly observed during menarche and perimenopause, it can present at any stage of reproductive life. AUB-O is a diagnosis of exclusion; other structural and physiologic etiologies of AUB should be ruled out by history, physical exam, or with laboratory analysis and imaging as appropriate.
The etiology of AUB-O is believed to be rooted in a disturbance in the hypothalamic-pituitary-ovarian axis. Physiologic anovulation is common at the beginning of reproductive life when the hypothalamic-pituitary-ovarian axis is not yet mature. Near menopause, recruitment of a follicle may occur early, in the luteal phase, followed by precocious maturation of the follicle. This "luteal out-of-phase event" then results in high levels of circulating estradiol and increased menstrual volume. Physiologic anovulation can also occur during lactation. Pathologic anovulation often occurs secondary to an endocrine dyscrasia with the polycystic ovarian syndrome (PCOS) being the most commonly implicated process. AUB-O can also be related to weight loss or weight gain, psychological stress, excessive exercise, or medications that affect dopamine metabolism.
Medications that correlate with ovulatory dysfunction include antiepileptics, such as valproate and lamotrigine,, and antipsychotics. Typical antipsychotics, more so than atypical antipsychotics, may cause hyperprolactinemia and subsequent AUB-O.
Abnormal uterine bleeding is a common problem. In the United States, there are reports of AUB at an annual rate of 53 per 1000 women in one study of reproductive-aged women. AUB-O can occur at any point in a patient’s reproductive lifetime. Following the establishment of regular menses, AUB-O accounts for most cases of AUB. In one study, anovulation was identified in 3.4 to 18.6% of menstruating women, depending on the diagnostic criteria used. It is most prevalent in patients that are :
The follicle is the primary functional unit in the ovary – responsible for germ cell development and steroid production. The peak of follicular maturation occurs at the midpoint of the ovulatory cycle. At this time, increased estrogen levels, followed by a surge in LH and FSH from the pituitary, results in ovulation. The follicular cells subsequently reorganize to become the corpus luteum. The corpus luteum supplies the hormone progesterone, which serves to stabilize the endometrium until implantation occurs. In the absence of ovulation, no corpus luteum forms; this results in lower levels of progestin, which leads to the persistence of proliferative endometrium. This unstable endometrial tissue is prone to irregular and heavy shedding. Additionally, the presence of high levels of estrogen unopposed by progesterone, are believed to contribute to increased vascular fragility and decreased vascular tone in the endometrium resulting in an increased volume of blood loss. Abnormal prostaglandin synthesis and prostaglandin receptor upregulation, increased fibrinolytic activity locally, and an increase in the activity of tissue plasminogen activator have all been implicated as mechanisms of abnormal uterine bleeding secondary to ovulatory dysfunction. The most common clinical features are heavy menstrual bleeding, irregular menses, and intermenstrual bleeding.
As with any medical condition, a detailed history and physical exam can significantly narrow the differential diagnosis, and help in selecting appropriate testing and imaging to evaluate for AUB. For adolescent patients, it is essential to take a history both with the patient’s parents present and again in their absence, as adolescent patients may not be willing to candidly discuss their symptoms and sexual practices in the presence of a parent. Irregular bleeding that is associated with AUB-O usually demonstrates by phases of amenorrhea that can last for months, and phases with either heavy bleeding or spotting. Typical premenstrual symptoms are usually absent. AUB-O should be suspected in women, especially at the extremes of reproductive age, who have an irregular bleeding pattern.
Signs/symptoms associated with known causes of AUB-O
Current Medications (include pills, powders, shakes, and supplements)
Family history with special focus on:
Initial evaluation for AUB-O begins with a general evaluation for AUB. If history or physical exam suggest a particular pathology, targeted testing can take place right away. At a minimum, all patients should have a blood or urine pregnancy test and complete blood count (CBC). The CBC is especially important if the patient complains of heavy menses, shortness of breath, lightheadedness, dizziness, fatigue, or pica as these symptoms could suggest anemia or thrombocytopenia. For patients with a recent pregnancy or miscarriage, a quantitative beta-hCG level can help to exclude trophoblastic disease.
Once pregnancy is ruled out, and anemia is either ruled-out or discovered and treated, attention can focus on the history, physical exam, and family history for clues as to the etiology of the bleeding. Appropriate testing for some concerning history elements:
Treatment of patients with positive findings on workup should target the specific pathology. For patients with no concerning findings or positive tests, it is reasonable to initiate medical management.
Menarche to 18 years:
19 to 39 years:
40 years to Menopause:
In cases of acute AUB, where there is a discrete episode of bleeding requiring immediate medical attention, the clinician should first stabilize the patient, then undergo an assessment with transvaginal ultrasonography to assess for uterine pathology and sonohysterography to evaluate for endometrial pathology.
Imaging may be used as a first-line evaluation tool if warranted by history or symptoms. It can also be used secondarily in patients who fail medical management. The most common modalities are hysteroscopy, transvaginal ultrasonography, MRI, and saline infusion sonohysterography.
The determination of treatment for AUB-O is through the etiology of the anovulation and the patient's therapeutic goals. Underlying endocrine abnormalities should be corrected. Normalization of eating disorders or stress, while challenging, can be achieved. If medications are causing ovulatory dysfunction, the patient should receive counsel regarding the indication for that medication, the risks/benefits of any alternatives, and any ways in which there can be mitigation of the effects of the drug. The choice of management often hinges on a patient's reproductive desires. Ultimately, patient safety is paramount, as ovulatory dysfunction may lead to endometrial hyperplasia or malignancy.
Medication management is the mainstay of treatment for AUB-O. The medical treatment options include progestin-only therapy and combined hormonal contraception. Progestin therapy is available in several forms, including an intrauterine device (IUD), intramuscular injection, and oral progestin-only hormonal pill. Non-contraceptive progestins can be prescribed in a cyclic manner (7 to 10 days each month) to induce regular withdrawal bleeding. The levonorgestrel-releasing IUD is appropriate for treatment in all age groups. Combined hormonal contraception is available as an oral pill, transdermal patch, and intravaginal ring. All of these options can protect the endometrium from hyperplasia or malignancy. Cyclic progestins or combined hormonal contraceptives may also improve the regularity of patients' bleeding if that is their desire.
If the patient desires fertility, contraceptives no longer align with her treatment goals. Brief courses of the above may be a strategy until the patient is ready to try to actively achieve pregnancy. Correction of underlying disorders, again, is essential. For women with polycystic ovarian syndrome, weight loss has been shown to lower circulating androgens. A reduction in body weight of as little as 5% may lead to the spontaneous resumption of normal menses. Pharmacologic weight loss agents may also improve ovarian function in patients with PCOS. These include orlistat, an inhibitor of intestinal lipid absorption, and sibutramine, which is an anorexic agent. Ovulation induction with medications such as letrozole or clomiphene citrate can also be an option for patients who are anovulatory and desire pregnancy. Clomiphene citrate has traditionally been used first-line for ovulation induction. Depending on the population, studies have shown a 6-month live birth rate of 20 to 40% with clomiphene. However, more recent studies have shown that letrozole may be more effective than clomiphene in PCOS patients, with a higher live birth rate (odds ratio 1.64) and higher clinical pregnancy rate (odds ratio 1.4). Insulin sensitizing agents, such as metformin, have also been used in women with PCOS. Particularly in obese women, combining metformin with clomiphene may increase pregnancy rates compared to clomiphene alone.
Surgical management for AUB-O is indicated in cases of medication treatment failure and/or medication contraindication. Laparoscopic ovarian drilling has been an option in patients with PCOS who desire fertility but have been resistant to medications such as clomiphene citrate. Unfortunately, there is no conclusive evidence that this procedure significantly improves clinical pregnancy rates, live birth rates, or miscarriage rates in these patients. Also, there is some concern regarding the long-term effects of this procedure on ovarian function. On the other hand, research exists that ovarian drilling reduces the rate of multiple pregnancies. For morbidly obese women with PCOS, gastric bypass surgery has been shown to normalize reproductive and metabolic abnormalities for many patients.
Due to the risk of hyperplasia and malignancy, endometrial tissue sampling, such as with endometrial biopsy or dilation and curettage, should be performed as a first-line test in women with AUB who are older than 45 years. Sampling should also be performed in younger women if they have a history of unopposed estrogen exposure, who have failed medical management, or who have persistent abnormal bleeding. In patients who have completed childbearing, hysterectomy is the definitive treatment for abnormal bleeding and treatment/prevention of endometrial hyperplasia. Hysterectomy has the benefit of being immediately effective and permanent.
Alternatively, endometrial ablation is a surgical procedure that has the potential to help many patients with abnormal uterine bleeding. However, endometrial ablation is not a recommendation in patients who have endometrial hyperplasia or malignancy. There have also been cases reported of patients having endometrial cancer after an ablation procedure, so caution is necessary when recommending this procedure to patients, such as those with AUB-O, who may already have an increased risk of developing an intrauterine malignancy. In one study, at 1-year treatment success (as defined by a Pictorial Blood Assessment Chart score of less than or equal to 75) was seen in 88.3% of patients treated with radiofrequency endometrial ablation and 81.7% of patients treated with resectoscopic endometrial resection. The amenorrhea rates in that study at one year were 41% for radiofrequency ablation and 35% for endometrial ablation with a resectoscope. With regards to failure, in one study with a mean follow-up of 39 months, 13.4% of women who had an endometrial ablation subsequently underwent a hysterectomy.
Abnormal uterine bleeding accompanying ovulatory dysfunction is a diagnosis of exclusion. The differential diagnosis includes all etiologies of AUB. The International Federation of Gynecology and Obstetrics (FIGO) created the PALM-COEIN system in 2011 to identify the common causes of AUB in non-pregnant women. The PALM group represents structural abnormalities that can be measured with imaging or histopathology and often undergo surgical treatment. The COEIN group represents non-structural etiologies that generally receive medical management.
O: ovulatory dysfunction
N: not yet classified
Specific causes of ovulatory dysfunction that merit consideration include:
The overall prognosis for patients with AUB-O is good. Symptoms can generally be managed medically with significant improvement in patient quality of life as a result. Identification and management of AUB-O can present complications such as hyperplasia or malignancy. Even in a worst-case scenario, the prognosis of endometrial cancer is relatively good compared to other gynecologic malignancies. Ovulation induction also can be very successful in patients desiring fertility. In one review, letrozole achieved live birth rates of 27.5%, and clomiphene citrate achieved live birth rates of 19.1%.
The most common complications of anovulation are infertility and irregular menses. Irregular menses can undergo improvement with hormonal contraception; however, if fertility is a patient desire, treatment with ovulatory induction agents such as clomiphene or letrozole may be appropriate. Depending on the primary physician’s level of comfort, this may require referral to an obstetrician-gynecologist. Chronic anovulation and unopposed estrogen can lead to endometrial hyperplasia and malignancy, and patients with AUB-O must be counseled regarding this dangerous complication of their irregular menses when discussing recommendations for treatment.
The most common complication of irregular heavy menses is iron-deficiency anemia, which can receive treatment with oral or intravenous iron therapy. Clinicians may recommend that a patient with symptomatic anemia who is taking oral contraceptives, skip the placebo week to prevent menstrual blood loss.
Sheehan syndrome (pituitary infarction) is a theoretical complication of endometrial ablation. Patients require counsel on this risk before being offered this treatment.
Specialty care can be helpful in the rapid diagnosis and treatment of AUB-O. Most patients can be reasonably managed in the primary care setting. An OBGYN consult is necessary cases with structural pathology or when surgical management is warranted. OBGYN consultation is also appropriate in patients with AUB-O who wish to conceive. A hematology-oncology referral is appropriate for patients with a known or suspected underlying bleeding disorder.
Counseling patients on the normal physiology of menarche and menopause may help to allay anxieties that correlate with symptoms of AUB-O during those transitional periods.
Patient education regarding what constitutes normal versus abnormal bleeding will help them to know when to make an appointment to discuss their bleeding with their physician. Many of the complications of AUB increase with the length of time between identifying and managing the abnormality.
Abnormal uterine bleeding with ovulatory dysfunction (AUB-O) is a frequently encountered complaint in both primary care and OBGYN clinics. Because there are many causes, it is crucial to have an interprofessional team dedicated to this health problem. Most patients initially present to the primary care clinician or nurse. A referral to a gynecologist should take place ASAP to prevent delays in diagnosis and treatment. While the patient is being worked up by the specialist, the primary clinicians should encourage the patient to maintain healthy body weight, discontinue smoking, eat a healthy diet, and exercise regularly.
Given the myriad of pharmaceutical options available for treatment, it is prudent to include a pharmacist at every step of the way fro agent selection, dosing, drug-drug interaction checking, and patient counseling. Nursing staff can also cover drug administration, answer patient questions, and help assess therapeutic effectiveness. Both pharmacy and nursing need open communication with the treating clinician so that all members of the interprofessional team are operating from the same information and can provide input to patient care to achieve optimal results. [Level V]
The ability to diagnose the condition quickly allows for more rapid initiation of treatment and specialty referral if necessary. Appropriate treatment of AUB-O has been shown to improve patient quality of life. [Level II].
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