Ovulation is the result of a maturation process that occurs in the hypothalamic-pituitary-ovarian (HPO) axis and is orchestrated by a neuroendocrine cascade terminating in the ovaries. Any alteration results in a failure to release a mature ovum, leading to anovulatory cycles. Anovulation may manifest in a variety of clinical presentations, from luteal insufficiency to oligomenorrhea.

Anovulation is a not a disease but a sign, in much the same way that polycystic ovaries are the manifestation of a much larger disease process.

Education for these patients should focus on an understanding of the underlying disorders to ensure compliance with both medical therapy and lifestyle modifications. For patient education resources, see Women's Health Center, as well as Anorexia Nervosa.


To understand anovulation, one must first understand what occurs during a normal ovulatory cycle. In normal physiology, ovulation is dependent on the presence of a functioning hypothalamic-pituitary-ovarian (HPO) axis. The arcuate nucleus within the hypothalamus is composed of a collection of neurons and, when stimulated, releases GnRH into the portal vessels of the pituitary stalk in a pulsatile fashion. GnRH stimulates receptors in the anterior pituitary gland to produce and secrete both LH and FSH. In women, FSH induces maturation of ovarian follicles and eventual production of estrogen, while LH modulates the secretion of androgens from the ovarian theca cells.[1] Estrogen, in turn, produces negative feedback on the pituitary gland.

As the follicle grows through accumulation of follicular fluid, the cohort of granulosa cells acquire the necessary receptors to respond to LH with increased formation of cyclic adenosine monophosphate (cAMP). During the midcycle, the estrogen levels in the circulation reach a concentration that causes a positive feedback action on LH secretion. This is called the LH surge. Generally speaking, approximately 16-24 hours after the LH peak, ovulation occurs with the extrusion of a mature oocyte from the graafian follicle and the formation of the corpus luteum.[2] These events are the culmination of a well-coordinated interplay between hormones and their appropriate receptors and proteolytic enzymes and prostaglandins acting in concert with one another, all directed by the HPO axis.

The system is so sensitive that even the slightest alteration in any of these factors can disrupt its fluidity and lead to anovulation.

When problems arise at any of the many different levels involved in the normal menstrual cycle, it is sometimes helpful to separate the levels by organ system. The hypothalamus and the anterior pituitary can be considered the neuroendocrine components by virtue of their proximity to each another, while the ovaries are a separate compartment. The third aspect that can be defective is the signaling process that occurs between these 2 areas.[2]

The initial stimulus must come from the hypothalamus in the form of gonadotropin-releasing hormone (GnRH); this decapeptide must be secreted in a pulsatile fashion within a critical range. For example, sexual maturity is not attained until the onset of regular ovulatory cycles, which may take months to years to occur. This maturation process is orchestrated by a neuroendocrine cascade and modified by autocrine and paracrine events in the ovaries, in which GnRH is the principal mediator.[3]

Any alteration in the GnRH pulse generator alters the hormonal milieu necessary for gonadotropin secretion and eventual response at the level of the ovary. Several entities (eg, hyperprolactinemia) are known to cause this type of dysregulation. Increasing levels of prolactin can cause a woman to progress from a deficient luteal phase to overt amenorrhea, usually associated with complete GnRH suppression. More common causes of dysregulation include stress, anxiety, and eating disorders, which are also associated with an inhibition of normal GnRH pulsatility through excessive hypothalamic activity of corticotrophin-releasing hormone and stimulation of beta-endorphins.[4]

How polycystic ovary syndrome (PCOS) is associated with anovulatory cycles has not been completely elucidated. Two associations with this disease entity are theorized to be at least somewhat responsible for its development. The first is the persistent elevation of LH levels in these patients; the second is the apparent arrest of antral follicle development at the 5- to 10-mm stage and consequent failure to enter the preovulatory phase of the cycle.[5] This evidence indicates that the disturbance is mainly a central defect that initiates the cascade of events leading to its onset.

Similarly, any condition, whether primary or secondary, that results in either a persistent elevation or an insufficient attainment of estrogen levels can inhibit ovulation through a disruption of the mechanisms that induce the LH surge. To achieve the corresponding changes within the cycle, estradiol levels must rise and fall appropriately.[2]



United States

Almost all women experience anovulatory cycles at some point in their reproductive lives. Yet, to attempt to determine the frequency of chronic anovulation in the general population is quite difficult because of underreporting. Estimates of chronic anovulation rates range from 6-15% of women during the reproductive years.

Interestingly, an article by Rasgon introduced a certain subset of the population as being at an increased risk for anovulatory disorders, stating that reproductive endocrine disorders, such as PCOS, hypothalamic amenorrhea, premature menopause, and hyperprolactinemia, are reportedly more common in women with epilepsy than in the general female population. The article further elaborates on the frequency of PCOS in patients who endure epilepsy independent of the use of antiepileptic therapy.[6] The risk of developing PCOS during valproate (VPA) treatment seems to be higher in women with epilepsy than in women with bipolar disorders; this might be due to an underlying neuroendocrine dysfunction. Gynecologists must be aware of the possibility that PCOS might be related to VPA use in this population of patients, and the risks and benefits of this treatment should be weighed in the presence of PCOS.[7]


Prognosis is generally favorable with appropriate and timely treatment.

Morbidities associated with chronic anovulation include hyperinsulinemia, insulin resistance, early onset of type 2 diabetes mellitus, dyslipidemia, cardiovascular disease, hypertension, infertility, endometrial hyperplasia, and endometrial cancer.


Complications of anovulation include the following:

Pregnancy complications

Women with PCOS who conceive are at increased risk for gestational diabetes, preeclampsia, cesarean delivery, and preterm and post-term delivery. Their newborns are at increased risk of being large for gestational age but are not at increased risk of stillbirth or neonatal death.[8]


In one study, the frequency of anovulation was greater among white women (9 of 63 [14.3%]) than black women (4 of 56 [7.1%]) or Hispanic women (7 of 102 [6.9%]), although these differences were not statistically significant.[9]


Anovulation occurs only in women of reproductive age.


Anovulation is physiologic at the extremes of reproductive age. During menarche, absence of ovulation is due to immaturity of the HPO axis, leading to an uncoordinated secretion of GnRH (pulsatility).

During perimenopause, ovarian factors and a dysregulation of feedback mechanisms are responsible.

When anovulation occurs outside of the perimenarchal or perimenopausal years, extrinsic and intrinsic causes must be excluded.


Past medical and surgical history

Obtain information about infections, history of pelvic surgery, anatomic anomalies, previous diagnosis of chromosomal abnormalities, past history of dilatation and curettage (history of postsurgical changes in menstrual flow, including amenorrhea and Asherman syndrome).

Past family history

Does/did the mother and/or sisters have similar symptoms?

History of pubertal development

When was the onset of menarche, pubarche, and growth spurt?

Detailed history of the menses

What is the current frequency, regularity or irregularity, length, and quantity of uterine bleeding?

Past reproductive history

Obtain information about pregnancy losses; antepartum, intrapartum, and postpartum complications, including dilatation and curettage, because of retained products of conception after an early pregnancy loss and after a normal vaginal delivery.

Past and current sexual activity

Obtain information about the number of partners, as well as a history of sexually transmitted diseases, painful intercourse, and vaginal symptoms (eg, burning, postcoital bleeding).

Contraceptive practices

What are the methods of contraception and duration of use, such as type of oral contraceptives and intrauterine devices (IUDs), including progestin-IUDs?

Dietary history

Has there been any recent weight gain or weight loss?


Obtain information about past and present medication use.

Psychologic history

Is there/has there been a history of depression, emotional lability, anxiety, and/or stress (including status of current relationships)?

History of previous malignancies

Obtain information about previous malignancies (eg, craniopharyngioma, leukemia, Hodgkin disease) and treatments received (eg, radiation, alkylating chemotherapeutic agents).

Review of symptoms

Has the patient experienced any of the following:


Obtain and document the patient's vital signs.


Evaluate the patient's voice, affect, and presentation (eg, disheveled, well-groomed).


Does the patient have facial acne (cystic), acanthosis nigricans (velvety dark patches usually found on the lateral aspects of the neck, axillae, and inner aspects of the thighs), stigmata of hepatic disease (telangiectasia, caput medusae), and/or violaceous striae usually in the flanks (Cushing syndrome)?

Head, eyes, ears, nose, and throat

Assess the following:


Evaluate the patient's Marshall-Tanner staging, areola (protuberance, pigmentation), secretions, shape of breasts (cylindrical as in exogenous estrogen exposure), decrease in breast size (androgen exposure), and/or presence of a shield chest (Turner syndrome).


Are murmurs present?


Assess for a linea alba, infraumbilical hair distribution, waist/hip ratio, and striae (as above).


Assess the mons pubis, Marshall-Tanner staging, male-female escutcheon, absence of pubic hair (androgen insensitivity syndrome), vulvar skin (hypoestrogenized), vulvovaginal mucosa (hypoestrogenized), and clitoris (clitoral index, >35 mm2). Perform a bimanual examination to exclude ovarian/adnexal masses, age-appropriateness of genitalia


Assess for the presence of lanugo (anorexia) versus male hair characteristics (hirsutism).


Volumes have been written on the different clinical entities associated with anovulation. Based on serum gonadotropins and ovarian hormones, clinicians are usually able to discern whether the ovulatory dysfunction is of central or ovarian origin. In the presence of PCOS, hormone levels are usually within the reference range, but they are accompanied by a wide array of clinical manifestations that may signal the presence of this disorder. The following describes the most important causes of anovulation and elaborates on their clinical and biochemical manifestations:

Polycystic ovary syndrome

First described in 1935 by Stein and Leventhal, PCOS is the most common endocrinopathy in women of reproductive age, with a prevalence of approximately 6.5%. Its cardinal features are hyperandrogenism and polycystic ovaries.[10] Clinically, PCOS is characterized by menstrual irregularities, hyperandrogenism, hyperinsulinemia, and long-term metabolic disturbances, such as diabetes mellitus, cardiovascular disease, and dyslipidemias.[11] Risk factors include history of premature adrenarche, family history of PCOS, and history of weight gain during the perimenarchal time.[12]

During the Rotterdam Conference of 2003, a revision of the diagnostic criteria the US National Institutes of Health conference initially proposed in 1990 was made to include the findings of polycystic ovaries. In 2006, the Androgen Excess Society has proposed a new set of criteria for the diagnosis of PCOS where the patient must demonstrate clinical or biological signs of hyperandrogenism plus additional criteria.

2003 consensus statement on PCOS

Any 2 of 3 of the following criteria must be present:

2015 American Association of Clinical Endocrinologists (AACE), American College of Endocrinology (ACE), and Androgen Excess and PCOS Society guidelines [14, 15]

Because of the disparity between follicular growth and steroidogenesis, Franks et al have proposed that a premature activation of LH-induced mitotic arrest, which occurs normally at the onset of the midcycle LH surge, is responsible for the ovulatory dysfunction noted in patients with PCOS.[5] Therefore, a combination of elevated LH levels with enhanced LH action may be responsible not only for the arrested growth of the follicles but also the increased production of estradiol.[16, 5]

Franks et al further hypothesize that these mechanisms may be intimately related to overproduction of cAMP at the level of the granulosa cell, whereby follicular arrest occurs simultaneously with excess androgen production.[5]

Hyperinsulinemia and insulin resistance

Insulin resistance, independent of obesity, has also been described as being pathognomonic of PCOS.[17] Impaired glucose tolerance has a prevalence of 30% and undiagnosed type 2 diabetes mellitus has a prevalence of 8-10% in women with PCOS.[12] Mechanisms have been proposed to account for the excess insulin production by the pancreas: (1) decreased insulin binding, (2) decreased insulin receptor numbers (down-regulation), and (3) postreceptor failures due to serine phosphorylation and eventual increase in pancreatic beta-cell stimulation.

Regardless of the cause, insulin resistance is predominantly seen peripherally, at the level of skeletal muscle, where 85-90% of circulating insulin is used. The compensatory hyperinsulinemia that occurs contributes to androgen excess by directly stimulating androgen production in the adrenal cortex and through a direct effect on granulosa cells and a simultaneous decrease of sex hormone–binding globulin (SHBG) in the ovaries.[18]

Increased insulin levels can lead to hyperplasia of the basal layer of the epidermis, resulting in velvety hyperpigmented areas of skin usually located on the back of the neck, the axilla, under the breasts, and inner thighs. These lesions are known as acanthosis nigricans.[12]


A centripetal, or apple-shaped, distribution of adipose tissue (waist-hip ratio, >0.88) is associated with a greater risk for hypertension, diabetes, and dyslipidemia.

Although many of the metabolic abnormalities can be alleviated with weight loss, they are still present. PCOS is neither caused by obesity nor cured by weight reduction.[19]

Hirsutism and acne

Hirsutism is the excessive growth of terminal hair, usually in a midline distribution or male-type pattern. The condition is characterized by a response of the pilosebaceous unit to androgens, causing a transformation of vellus to terminal hair in androgen-dependent areas.[20] Hirsutism is classified into the following groups: (1) idiopathic, (2) drug-induced, and (3) due to androgen excess. Most cases of hirsutism result from a combination of mildly increased androgen production and increased skin sensitivity to androgens. Cases that are not androgen-dependent (eg, those caused by medications or familial hypertrichosis) are best diagnosed by physical examination.

Approximately 95% of women with androgen-dependent hirsutism have both adrenal and ovarian causes. The most common cause of hirsutism is PCOS. Additionally, different cultures and races tend to have or display hair in different amounts and locations. These patients are generally classified into the first group in the presence of normal levels of circulating androgens.

If excess androgens are the primary cause of the hirsutism, androgen receptors are found in the anagen (active) phase in the follicles' dermal papillae and associated sebaceous glands, where stimulation is provided by the more potent androgens testosterone and dihydrotestosterone. In excessive amounts, they cause hirsutism, except on the scalp, where androgenic alopecia is induced.[21]

A clinical tool that offers an objective assessment of the hirsute patient is the modified Ferriman-Gallwey scale proposed by Hatch and coworkers. It takes into account 9 of the 11 sites originally described, each receiving a score of 0-4 (maximum). A score of 8 or more is considered significant.

The presence of hirsutism in conjunction with other signs of virilization should alert the physician to the possibility of androgen-producing tumors of adrenal or ovarian origin.

Acne vulgaris, usually seen in adolescence, is directly associated with the level of circulating androgen concentration. In a study of postpubertal women with the chief complaint of acne, PCOS was diagnosed in 37% of participants.[22]

Chronic anovulation

Chronic anovulation with estrogen present can occur in a variety of endocrine disorders. It can occur in women with PCOS and other functional abnormalities, including those with Cushing syndrome, hyperthyroidism, hypothyroidism, late-onset adrenal hyperplasia resulting from 21-hydroxylase deficiency, 11-alpha-hydroxylase deficiency, or 3-beta-hydroxysteroid dehydrogenase deficiency.

Chronic anovulation may also involve tumors of the ovary, including granulosa-theca cell tumors, Brenner tumors, cystic teratomas, mucinous cystadenomas, and Krukenberg tumors. These tumors secrete excess estrogen or androgens that undergo aromatization in extraglandular sites.

Premature ovarian failure

Premature ovarian failure (POF), also known as hypergonadotropic hypogonadism, occurs when oocytes and the surrounding cells are lost prior to 40 years of age. Because the ovaries do not respond to FSH and LH (hypogonadism), there is no negative feedback creating a hypergonadotropic state. POF is diagnosed with 2 serum FSH levels greater than 40 mIU/mL at least 1 month apart. The incidence of POF has been estimated by Coulam in 1986 as 1 in 1,000 women younger than 30 years, and 1 in 100 women younger than 40 years. Gonadal dysgenesis is the most frequent cause of POF, two thirds of which are a result of a deletion on an X chromosome. Although a normal complement of germ cells is present in the early fetal ovary, oocytes undergo accelerated atresia, and the ovary is replaced by a fibrous streak.[23]

Cushing syndrome

Cushing syndrome is characterized by hypercortisolism. Its clinical manifestations encompass a spectrum of symptoms, the severity of which is often influenced by the presence or absence of androgen excess. Progressive obesity and abnormal waist/hip ratio are not uncommon, although the limbs are often spared. Frequently, patients experience proximal muscle weakness and cannot rise from a sitting position. Patients can also be hypertensive as a result of mineralocorticoid excess.

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Anovulation. On the left is an unaffected patient aged 12 years. On the right is the same patient aged 13 years after developing Cushing disease.

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Anovulation. Left adrenal mass discovered incidentally.

Normally, cortisol-releasing hormone and hypothalamic factors are released into the hypophyseal portal blood and carried to the anterior pituitary, where they stimulate the release of adrenocorticotropic hormone (ACTH). In Cushing disease, the increased plasma ACTH concentrations stimulate increased adrenocorticoid secretion, thus inhibiting hypothalamic corticotropin-releasing hormone (CRH) secretion and other factors from the pituitary. This aberration in the cycle, as well as changes in secretory patterns, are thought to influence the mechanisms involved in ovulatory function. Although the exact mechanisms have not been elucidated, it is believed that hypercortisolism and adrenal hyperandrogenism suppress gonadotropin secretion with impaired LH response to GnRH.

Adrenal insufficiency

Adrenal insufficiency can be due to a variety of causes, including deficient hypothalamic secretion of CRH, deficient pituitary secretion of ACTH, or destruction of the adrenal cortex (Addison disease, primary adrenal insufficiency).

Adrenal androgen deficiency results in loss of axillary and pubic hair in women and decreased libido. Women with autoimmune adrenal insufficiency are at increased risk of premature ovarian failure and anovulation.

Congenital adrenal hyperplasia

CAH encompasses a group of autosomal recessive disorders caused by an inherited deficiency of enzymes involved in cortisol synthesis in the adrenal cortex.

These disorders, listed in decreasing order of frequency, include a deficiency of 21-hydroxylase, 11-alpha-hydroxylase, and 3-beta-hydroxysteroid dehydrogenase. Hyperandrogenism induces a disruption of the HPO axis and consequently leads to menstrual irregularities or anovulatory cycles.


Some women experience oligomenorrhea. Increased thyroid hormone levels raise SHBG production and therefore serum levels, reflecting increased tissue response to these hormones. Total estrogen and testosterone circulating levels are also increased.

The levels of active or free fractions of these sex steroids are often reduced. Treatment of hyperthyroidism results in regular ovulatory menstrual cycles and fertility. Mid luteal phase progesterone levels in thyrotoxic women improve after treatment.


Women with hypothyroidism often experience the spectrum of menorrhagia and metrorrhagia. Patients with hypothyroidism have reduced levels of SHBG and decreased levels of circulating estrogens and testosterone. Follicle-stimulating hormone (FSH) and LH levels are also reduced. Hypothyroidism can cause aberrations in coagulation. It is believed that a hypothyroid state leads to decreased levels of factors VII, VIII, IX, and XI. Hypothyroidism is the most common endocrinologic condition associated with anovulation.

In addition, hypothyroidism alters steroid metabolism and clearance, which may lead to endometrial dysfunction. This evidence supports the fact that menorrhagia is a symptom of hypothyroidism. These symptoms are easily treated with thyroid hormone replacement. Hypothyroidism leads to increased levels of thyroid-releasing hormone and therefore increased levels of thyroid-stimulating hormone (TSH [ie, thyrotropin]) and prolactin. Hyperprolactinemia from long-standing primary hypothyroidism may be responsible for varying degrees of ovulatory dysfunction.


Prolactin excess manifests clinically as infertility, oligomenorrhea, and amenorrhea. The mechanism seems to involve the inhibition of pituitary gonadotropins via suppression of GnRH pulsatility. As a result of this inhibition, serum gonadotropin levels are significantly decreased, causing secondary hypogonadism. Mild hyperprolactinemia may cause infertility, even in the presence of a regular menstrual cycle, while elevated levels of prolactin may cause galactorrhea.

Patients with hyperprolactinemia must always have a complete history and physical examination to rule out easily correctable causes of hyperprolactinemia. Some of these causes include medication usage (eg, exogenous estrogens, neuroleptics, antidepressants, some antipsychotic medications). MRI should be obtained to rule out a mass lesion in the hypothalamic-pituitary region (see image below). Usually, imaging is not warranted unless levels surpass 100 ng/mL after a negative pregnancy test result. Normalization of prolactin levels through the adjustment of current medications or addition of bromocriptine restores ovulation and fertility.

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Anovulation. MRI showing a nonenhancing area in the pituitary consistent with a microadenoma in a patient with hyperprolactinemia.

Eating disorders and aggressive exercise habits

Anorexia is defined as a serious, usually chronic psychiatric disorder of an indolent nature that can be life-threatening if unrecognized. The condition is characterized by a patient's inability to maintain a weight of at least 85% of her ideal body weight. Other essential features of the disorder include an intense fear of gaining weight, a distorted body image (body dysmorphic syndrome), and amenorrhea.

Below-average body weight is not in itself enough to cause amenorrhea; the numerous mechanisms intimately related to profound weight loss are also factors. Frisch and McArthur have suggested that a minimum of 17% body fat is required for the initiation of menses, and at least 22% body fat is necessary for menstrual cyclicity.[24] Leptin, a serum hormone secreted by adipose tissues in proportion to total body lipid stores, has recently received much attention for its role in the pathogenesis of weight and menstrual control in these patients.

A diurnal secretion pattern has been established in women of reproductive age who have a normal body mass index (BMI). Athletes with exercise-induced amenorrhea exhibit leptin levels similar to those of prepubertal girls and consequently lose the diurnal release pattern. Andrico et al demonstrated that leptin levels are significantly lower in patients with functional hypothalamic amenorrhea compared with those of controls who were matched for both age and weight.[25] These investigators suggest that energy balance can interfere with the ratios of body weight to leptin and BMI to leptin in functional hypothalamic amenorrhea.

The consequences of exercise-induced amenorrhea are similar to those of estrogen deficiency. These patients are at an increased risk of osteopenia and, eventually, osteoporosis if not treated expeditiously. Vaginal atrophy and infertility issues are generally the rule. A multidisciplinary approach is therefore necessary when treating these patients in order to address underlying issues and physical manifestations.

Amenorrhea is a consequence of multiple alterations in female hormonal pathways. Anorexic women show a 24-hour pattern of FSH and LH similar to that observed in prepubescent children. They may also exhibit altered ACTH levels and characteristically low triiodothyronine (T3) levels.

The mechanisms involved in amenorrhea caused by excessive exercise or anorexia nervosa are not well understood. However, links seem to exist among malnutrition, chronic disease, and hormonal alterations. Excessive levels of endogenous opioids, with a concomitant increase in CRH secretion, inhibit GnRH release as well. Patients can expect an increased risk of infertility, vaginal and breast atrophy, and osteopenia.

Bulimia nervosa is a another eating disorder in which a female consumes large amounts of food followed by inappropriate behavior to avoid weight gain,[26] most commonly by inducing vomiting, otherwise known as the binge-and-purge cycle. Fluctuations or extreme weight loss are not common. However, these patients usually experience menstrual irregularities or anovulatory cycles. Commonly, they have halitosis and dental caries. They may also exhibit strange behavior when eating in a group setting. Bulimic patients usually prefer to eat during times that do not coincide with those of other members of the household.

The pathophysiology of anovulation in bulimic women is very similar to that of anorexic women, although the neuroendocrine disturbances are significantly milder than in anorexia. LH levels are reduced because of a blunting of the GnRH pulse generator, which leads to the menstrual disturbances commonly observed. Thyroid function is altered, as well as glucose tolerance, with accompanying hypercortisolemia.

Hypothalamic and pituitary causes

The presence of GnRH is essential; studies have shown that the administration of a GnRH antagonist to women at midcycle prevents the LH surge. The physiologic capabilities of the hypothalamic GnRH neurons and pituitary gland are subject to disruption by several pathologic entities, including tumors, trauma, and irradiation.

Hypothalamic causes include tumors, trauma, and irradiation

Note the following:

Pituitary causes include trauma and irradiation.

Note the following:

Nonneoplastic causes of hypopituitarism include empty sella syndrome, Sheehan syndrome, pituitary apoplexy, and pituitary adenomas.

Note the following:

Laboratory Studies

Laboratory evaluation in patients with anovulation includes the following:

Workup for autoimmune disorders may be considered when initial test results are uninformative and may include the following studies:

Other tests may include the following:

Imaging Studies

Radiologic studies in the evaluation of patients with anovulation includes the following:


Endometrial biopsy may be performed to exclude endometrial hyperplasia. An endometrial biopsy should be performed in all women older than 35 years who have irregular uterine bleeding, whether in the presence of anovulatory or ovulatory cycles. Biopsy is also indicated in women younger than 35 years who have a long-standing history of anovulation and concomitant risk factors for endometrial hyperplasia, such as obesity (unopposed estrogenic environment). The most important aspect is that age should not be a factor in deciding whether to perform an endometrial biopsy.

Histologic Findings

Endometrial glands undergo mild architectural changes, including cystic dilation reminiscent of a proliferative endometrium, because of prolonged, excessive endometrial stimulation by estrogens. Unscheduled breakdown of the stroma may also occur, with no evidence of the endometrial secretory activity usually observed as a result of a functioning corpus luteum and subsequent production of progesterone.

Medical Care

The medical management of anovulation is complex because it entails initiating a multitiered approach to patient care.

First and foremost, the clinician should be well acquainted with the most common etiologies and able to rule them out, specifically those that can pose serious dangers to a patient's immediate health. Fortunately, anovulation usually manifests in a clinical setting geared toward the treatment of chronic diseases and conditions, which provides the precision necessary for an accurate diagnosis. Despite this, patients often have a history of multiple doctor visits because of inadequate or unsuccessful treatment by other physicians secondary to a misdiagnosis. The care of these patients must be tailored to their individual presentations and the specific disease entities responsible for anovulation. A holistic approach, consultation with other specialists, and routine follow-up should be the rule, not the exception.

Acute bleeding secondary to anovulation

Most causes of dysfunctional uterine bleeding respond to either oral or intravenous estrogen. Treatment using the parenteral route can be initiated with estrogen (Premarin) 25 mg IV q4h by accelerating the mitotic activity at the level of the endometrium. If no response is seen after 24 hours, suction dilation and curettage is warranted.

If the bleeding is not as vigorous, high-dose birth control pills (totalling 3 pills/d for 7 d), followed by continuation of oral contraceptives for a minimum of 3 months, has equal efficacy in reestablishing the endometrium.

Because of the menstrual irregularities associated with anovulation, anemia is a concern and must be treated with allogeneic blood transfusion if blood parameters fall below critical levels. Intravenous estrogen (Premarin) or high-dose combined oral contraceptives may be needed to ameliorate or terminate the acute bleeding episode. Dilation and curettage should never be the first-line treatment in this clinical setting; however, in the case of intractable bleeding, it may be the only alternative. Subtotal or total hysterectomy is rarely, if ever, necessary.

Anovulation and amenorrhea

Pregnancy test and hormonal studies measuring thyroid function, prolactin levels, and gonadotropin levels should be obtained. These hormonal assays should be followed by a progestational challenge to evaluate the endometrial lining and the presence of a hypoestrogenic state.

The first possibility is normal levels with a positive withdrawal bleed. This indicates anovulation and unopposed estrogen stimulation. Treatment is focused on providing progesterone support and cyclicity in the form of oral contraceptives or progestin alone, which is paramount in the prevention of endometrial hyperplasia.

If TSH or prolactin levels are elevated, correcting the primary problem is usually enough to attain ovulatory cycles once again.

If gonadotropin levels are low or normal, a diagnosis of hypogonadotropic hypogonadism is assumed and a space-occupying lesion versus hypothalamic suppression due to exercise or weight fluctuations (eg, anorexia nervosa, bulimia) must be ruled out. Treatment again focuses on the cause of the suppression.

If FSH and LH levels are elevated (hypergonadotropic hypogonadism), the problem is usually related to an absence of inhibitory signals that originate from the ovary under normal conditions; therefore, ovarian failure is presumed. Generally, other signs and symptoms of hypoestrogenism, such as vaginal dryness, emotional lability, and hot flushes due to vasomotor spasm, help confirm the diagnosis. If this occurs before age 30 years, a karyotype is necessary to rule out the presence of a Y chromosome or fragile X premutation. Owing to the high rate of malignant germ cell tumors in this setting, a gonadectomy must be performed immediately. Other considerations are certain autoimmune and infectious processes that can destroy ovarian tissue through infiltration of autoimmune complexes.

Surgical Care

Surgical care is usually indicated to resolve the underlying cause for the anovulation, typically when medical therapy has failed.

Surgery is also indicated in rare cases, such as a macroadenoma of the pituitary with unrelenting growth eliciting severe symptoms (eg, headaches, bitemporal hemianopsia, diplopia). In the event of a benign or malignant neoplasm of ovarian or adrenal origin, exploratory laparotomy, resection, and staging are indicated.

Ovarian drilling and ovarian wedge resection are other surgical modalities used in the treatment of anovulation due to PCOS, with a spontaneous ovulation rate of more than 80% after the procedure.

While dilation and curettage is never first-line therapy for acute bleeding, practitioners are sometimes left with no other option. In even rarer cases, hysterectomy may be the only solution to the profound anemia stemming from acute blood loss.

Bariatric surgery has been advocated in the surgical treatment of severe obesity when accompanied by medical complications in which weight loss could be curative. Gastroplasty, vertical banded gastroplasty, gastric banding, and vertical stapling are commonly used but are less effective than the roux-en-Y gastric bypass. Typically patients with a BMI greater than 40 are candidates for surgery, assuming past attempts at medical treatment have failed, although patients with a BMI of 35-40 and underlying life-threatening medical problem may be considered as well.[35]


Consider consultations with the following specialists:


When considering a specific diet in the setting of anovulation, the principal focus must be in reference to the endocrinologic and metabolic derangements observed in PCOS. Therefore, a well-structured low-carbohydrate/low-cholesterol regimen is imperative because of the insulin resistance and cardiovascular risks commonly occurring in these patients.

The effectiveness of organized weight loss programs such as Weight Watchers, Curves, or Jenny Craig has been well documented to improve the recidivism rate in overweight patients attempting to lose weight when done in conjunction with counseling and support group initiatives.


Cardiovascular exercise helps offset the inherent risks associated with PCOS.

Weight-bearing exercise should be recommended for patients with hypoestrogenic states, such as premature ovarian failure, when estrogen replacement is a contraindicated.

Medication Summary

Medical therapy of anovulation should be directed at reversal of the primary underlying cause and tailored to the individual patient.

Clomiphene citrate (Serophene, Clomid, Milophene)

Clinical Context:  Stimulates release of pituitary gonadotropins. Acts as an antiestrogen to decrease negative estrogen feedback on hypothalamus. In addition, may have effects on pituitary gland and ovaries and can induce ovulation in women with hypothalamic amenorrhea. Improves folliculogenesis and, therefore, ovarian function during luteal phase.

Class Summary

Used for ovulation induction.

Levothyroxine (Synthroid, Levoxyl, Levothroid)

Clinical Context:  If luteal phase dysfunction is caused by hypothyroidism, correction of endocrine disease results in normal luteal phase.

Class Summary

Used to correct hypothyroidism.

Norethindrone/ethinylestradiol (Ortho-Novum, Ovcon 35, Ovcon 50)

Clinical Context:  In young females, low-dose PO contraception generally is an excellent method of hormone replacement. Any low-dose combination pill with 35 mcg of ethinyl estradiol or less or any progestin is appropriate. Also useful because, on occasion, these women may spontaneously ovulate and become pregnant.

Norgestimate/ethinyl estradiol (Ortho-Prefest, Ortho TriCyclen, Ortho-Cyclen)

Clinical Context:  In young females, low-dose PO contraception generally is an excellent method of hormone replacement. Any low-dose combination pill with 35 mcg of ethinyl estradiol or less or any progestin is appropriate. Also useful because, on occasion, these women may spontaneously ovulate and become pregnant.

Class Summary

Used for hormone replacement.

Alendronate (Fosamax)

Clinical Context:  Inhibits bone resorption via actions on osteoclasts or osteoclast precursors. Used to treat osteoporosis in both men and women. May reduce bone resorption and incidence of fracture at spine, hip, and wrist by approximately 50%. Should be taken with a large glass of water at least 30 min before eating and drinking to maximize absorption. Because of possible esophageal irritation, patients must remain upright after taking the medication. Since it is renally excreted, not recommended in patients with moderate-to-severe renal insufficiency (ie, CrCl < 30 mL/min or serum Cr > 3 mg/dL); use in perirenal transplantation is limited.

Class Summary

Analogs of pyrophosphate and act by binding to hydroxyapatite in bone matrix, thereby inhibiting dissolution of crystals. Prevent osteoclast attachment to the bone matrix and osteoclast recruitment and viability.

Metformin (Glucophage)

Clinical Context:  Reduces hepatic glucose output, decreases intestinal absorption of glucose, and increases glucose uptake in the peripheral tissues (muscle and adipocytes). Major drug used in obese patients who have type 2 diabetes mellitus.

Class Summary

May increase glucose uptake in peripheral tissues.

Finasteride (Proscar, Propecia)

Clinical Context:  Blocks conversion of testosterone to its more active metabolite, dihydrotestosterone. More effective when used in combination with OCPs.

Spironolactone (Aldactone)

Clinical Context:  Aldosterone antagonist that inhibits ovarian and adrenal production of androgens. Competes with dihydrotestosterone binding at hormone receptor sites on hair follicle cells. Also reduces 17alpha-hydroxylase activity, lowering plasma levels of testosterone and androstenedione.

Class Summary

May inhibit androgen feedback on pituitary gland.

Fludrocortisone (Florinef)

Clinical Context:  Partial replacement therapy for primary and secondary adrenocortical insufficiency.

Class Summary

May be used to correct adrenal insufficiency.

Ketoconazole (Nizoral)

Clinical Context:  Inhibits steroid synthesis at the level of 17-alpha-hydroxylase/17,20-lyase, a key enzyme in sex steroid production. Also inhibits testosterone binding to its binding globulin. In some cases, especially in children with markedly advanced bone age, a rapid decrease in sex hormone levels may trigger true central puberty. In this event, add GnRH analogs to the treatment regimen.

Class Summary

Inhibit a variety of cytochrome P-450 enzymes, including 11beta-hydroxylase and 17-alpha-hydroxylase, which in turn, inhibit steroid synthesis.

Pergolide (Permax)

Clinical Context:  Pergolide withdrawn from US market. Inhibits secretion of prolactin (PRL); causes a transient rise in serum concentrations of GH and decreases serum concentrations of LH.

Class Summary

Directly stimulate postsynaptic dopamine receptors. The dopaminergic neurons in the tuberoinfundibular process modulate the secretion of prolactin from the anterior pituitary by secreting a prolactin inhibitory factor (believed to be dopamine).

Pergolide was withdrawn from the US market March 29, 2007, because of heart valve damage resulting in cardiac valve regurgitation. It is important not to abruptly stop pergolide. Health care professionals should assess patients' need for dopamine agonist (DA) therapy and consider alternative treatment. If continued treatment with a DA is needed, another DA should be substituted for pergolide. For more information, see FDA MedWatch Product Safety Alert and Medscape Alerts: Pergolide Withdrawn From US Market.

Medroxyprogesterone acetate (Provera, Cycrin, Depo-Provera)

Clinical Context:  Derivative of progesterone. Androgenic and anabolic effects have been noted, but apparently is devoid of significant estrogenic activity. Parenterally administered dosage form inhibits gonadotropin production, which in turn, prevents follicular maturation and ovulation. Available data indicate that this does not occur when the usually recommended PO dose is administered qd. When orally administered in the recommended doses to women adequately exposed to exogenous or endogenous estrogen, transforms the proliferative endometrium into a secretory one.

Class Summary

May be used for endometrial stabilization and organization of basal layer in chronic anovulation.

Estrogens, conjugated/equine (Premarin)

Clinical Context:  May be used for restoration of regular menstrual cycles, which may prevent endometrial hyperplasia associated with anovulation. Improvements of hyperandrogenic effects occur in 60-100% of women but usually require a minimum of 6-12 mo of use. A pregnancy test should be performed before initiating therapy. If the woman has had no menstrual period for 3 mo, withdrawal bleeding should be induced by administration of 5-10 mg of medroxyprogesterone acetate (Provera) qd for 10 d; therapy is then begun with OCPs.

Class Summary

May be used to build endometrial lining in acute and chronic anovulation.

Ibuprofen (Advil, Motrin, Excedrin IB)

Clinical Context:  Used for reduction in uterine bleeding and dysmenorrhea associated with anovulatory cycles. Blocks formation of prostacyclin, an antagonist of thromboxane, a substance that accelerates platelet aggregation and initiates coagulation. Because NSAIDs inhibit blood prostacyclin formation, they might effectively decrease uterine blood flow.

Class Summary

Reduce blood loss by 30-50% in cases of anovulatory bleeding.

Letrozole (Femara)

Clinical Context:  Reduces circulating estrogen inhibiting the estrogen negative feedback of the HPA. Results in increased secretion of FSH and thus ovarian follicle development.

Anastrozole (Arimidex)

Clinical Context:  Aromatase inhibitor that significantly lowers serum estradiol concentrations by inhibiting the conversion of adrenally generated androstenedione to estrone. Used as first-line treatment of breast cancer in postmenopausal women with hormone receptor positive or hormone receptor unknown locally advanced or metastatic disease. Also used to treat advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy.

Class Summary

These agents inhibit aromatase activity, which causes serum estrogen levels to reduce.

Follitropin alfa (Gonal-F)

Clinical Context:  Exogenous FSH stimulates proliferation of granulosa cells and follicular growth. Release of follicles is stimulated by human chorionic gonadotropin. Safety and efficacy of gonadotropin therapy depends on careful monitoring and should only be managed by a specialist.

Class Summary

These agents stimulate ovarian follicular growth.

Further Outpatient Care

Long-term health consequences, depending on their etiologic origin, include an increased risk for obesity, diabetes mellitus, heart disease, dyslipidemia, hypertension, endometrial hyperplasia, and infertility, and treatment must be focused on addressing these health concerns in addition to the primary causes (ie, PCOS). Therefore, aggressive preventative health care interventions are warranted, including interventions that lower cardiovascular risk factors through diet, exercise, and judicious use of statin medications when appropriate, as well as endometrial biopsy in the setting of chronic irregular bleeding regardless of age for the diagnosis of endometrial hyperplasia. Assessment must be continued at routine intervals (eg, every 4-6 mo).


Armando E Hernandez-Rey, MD, Consulting Staff, Reproductive Endocrinology and Infertility, Robotic and Minimally Invasive Surgery, Conceptions: Center for Fertility & Genetics of Florida; Assistant Professor of Women's Health, Florida International University College of Medicine

Disclosure: Received consulting fee from Inuitive Surgical for independent contractor; Received consulting fee from Vita Med MD for speaking and teaching.

Specialty Editors

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Frances E Casey, MD, MPH, Director of Family Planning Services, Department of Obstetrics and Gynecology, VCU Medical Center

Disclosure: Nothing to disclose.

Chief Editor

Richard Scott Lucidi, MD, FACOG, Associate Professor of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Virginia Commonwealth University School of Medicine

Disclosure: Nothing to disclose.


The authors and editors of Medscape Drugs & Diseases gratefully acknowledge the contributions of previous authors Krystene I Boyle, MD, Cassandra Blot, MD, and Peter G McGovern, MD, to the development and writing of this article.


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Anovulation. Polycystic ovary. Courtesy of Jairo E. Garcia, MD.

Anovulation. On the left is an unaffected patient aged 12 years. On the right is the same patient aged 13 years after developing Cushing disease.

Anovulation. Left adrenal mass discovered incidentally.

Anovulation. MRI showing a nonenhancing area in the pituitary consistent with a microadenoma in a patient with hyperprolactinemia.

Anovulation. Polycystic ovary. Courtesy of Jairo E. Garcia, MD.

Anovulation. On the left is an unaffected patient aged 12 years. On the right is the same patient aged 13 years after developing Cushing disease.

Anovulation. Left adrenal mass discovered incidentally.

Anovulation. MRI showing a nonenhancing area in the pituitary consistent with a microadenoma in a patient with hyperprolactinemia.