Disorders of ovulation include oligoovulation and anovulation:

- Oligoovulation is infrequent or irregular ovulation (usually defined as cycles of ≥36 days or <8 cycles a year)

- Anovulation is absence of ovulation when it would be normally expected (in a post-menarchal, premenopausal woman). Anovulation usually manifests itself as irregularity of menstrual periods, that is, unpredictable variability of intervals, duration, or bleeding. Anovulation can also cause cessation of periods (secondary amenorrhea) or excessive bleeding (dysfunctional uterine bleeding).

During the transition to menopause, menstrual patterns can show shorter cycling (by 2–7 days); longer cycles remain possible. There may be irregular bleeding (lighter, heavier, spotting). Dysfunctional uterine bleeding is often experienced by women approaching menopause due to the hormonal changes that accompany the menopause transition. Spotting or bleeding may simply be related to vaginal atrophy, a benign sore (polyp or lesion), or may be a functional endometrial response. The European Menopause and Andropause Society has released guidelines for assessment of the endometrium, which is usually the main source of spotting or bleeding.

In post-menopausal women, however, any genital bleeding is an alarming symptom that requires an appropriate study to rule out the possibility of malignant diseases.

Symptoms that may appear during menopause and continue through postmenopause include:

- painful intercourse

- vaginal dryness

- atrophic vaginitis – thinning of the membranes of the vulva, the vagina, the cervix, and the outer urinary tract, along with considerable shrinking and loss in elasticity of all of the outer and inner genital areas.

Dysmenorrhea (or dysmenorrhoea), cramps or painful menstruation, involves menstrual periods that are accompanied by either sharp, intermittent pain or dull, aching pain, usually in the pelvis or lower abdomen.

Other physical symptoms of menopause include lack of energy, joint soreness, stiffness, back pain, breast enlargement, breast pain,

heart palpitations, headache, dizziness, dry, itchy skin, thinning, tingling skin, weight gain, urinary incontinence,

urinary urgency,

interrupted sleeping patterns, heavy night sweats, hot flashes.

Irregular cycles or irregular periods is an abnormal variation in length of menstrual cycles. A female usually experiences cycle length variations of up to eight days between the shortest and longest cycle lengths. Lengths ranging between eight and 20 days are considered moderately irregular. Variation of 21 days or more is considered very irregular.

Alternatively, a single menstruation period may be defined as irregular if it is shorter than 21 days or longer than 36 days. If they are regularly shorter than 21 days or longer than 36 (or 35) days, the condition is termed polymenorrhea or oligomenorrhea, respectively.

Other types of conditions that can be referred to by "irregular menstruation" include:

- Metrorrhagia, which generally refers to vaginal bleeding that occurs between the expected menstrual periods. The distinction between irregular cycle lengths and metrorrhagia is not always clear. It may depend on whether the bleeding is regarded as marking the menstrual period (favoring the term "irregular cycles") or being separate from it (favoring the term "metrorrhagia").

- Oligomenorrhea generally refers to infrequent menstruation, More strictly, it is menstrual periods occurring at intervals of greater than 35 days, with only four to nine periods in a year. Menstrual periods should have been regularly established before the development of infrequent flow and often (but not always) involves irregular intervals. In contrast to "irregular cycles", the interval between one cycle and the next may be consistent but can be regarded as "irregular" compared to the cycle length of a female without oligomenorrhea. Women with oligomenorrhea often have irregular cycles as well.

- "Polymenorrhea" is the medical term for cycles with intervals of 21 days or fewer. It can be regarded as the opposite of oligomenorrhea.

Anovulation is usually associated with specific symptoms. However, it is important to note that they are not necessarily all displayed simultaneously. Amenorrhea (absence of menstruation) occurs in about 20% of women with ovulatory dysfunction. Infrequent and light menstruation occurs in about 40% of women with ovulatory dysfunction. Another potential symptom is irregular menstruation, where five or more menstrual cycles a year are five or more days shorter or longer than the length of the average cycle. Absence of mastodynia (breast pain or tenderness) occurs in about 20% of women with ovulatory problems. Also possible is increased body mass and facial hair, which is relatively easy to treat, and is often associated with PCOS, or polycystic ovary syndrome.

There are two primary ways to classify amenorrhoea. Types of amenorrhoea are classified as primary or secondary, or based on functional "compartments". The latter classification relates to the hormonal state of the patient that hypo-, eu-, or hypergonadotropic (whereby interruption to the communication between gonads and follicle stimulating hormone (FSH) causes FSH levels to be either low, normal or high).

- By primary vs. secondary: Primary amenorrhoea is the absence of menstruation in a woman by the age of 16. As pubertal changes precede the first period, or menarche, female children by the age of 14 who still have not reached menarche, plus having no sign of secondary sexual characteristics, such as thelarche or pubarche—thus are without evidence of initiation of puberty—are also considered as having primary amenorrhoea. Secondary amenorrhoea is where an established menstruation has ceased—for three months in a woman with a history of regular cyclic bleeding, or nine months in a woman with a history of irregular periods. This usually happens to women aged 40–55. However, adolescent athletes are more likely to experience disturbances to the menstrual cycle than athletes of any other age. Amenorrhoea may cause serious pain in the back near the pelvis and spine. This pain has no cure, but can be relieved by a short course of progesterone to trigger menstrual bleeding.

- By compartment: The reproductive axis can be viewed as having four compartments: 1. outflow tract (uterus, cervix, vagina), 2. ovaries, 3. pituitary gland, and 4. hypothalamus. Pituitary and hypothalamic causes are often grouped together.

Amenorrhoea is the absence of a menstrual period in a woman of reproductive age. Physiological states of amenorrhoea are seen, most commonly, during pregnancy and lactation (breastfeeding), the latter also forming the basis of a form of contraception known as the lactational amenorrhoea method. Outside the reproductive years, there is absence of menses during childhood and after menopause.

Amenorrhoea is a symptom with many potential causes.

Primary amenorrhoea (menstrual cycles never starting) may be caused by developmental problems, such as the congenital absence of the uterus or failure of the ovary to receive or maintain egg cells. Also, delay in pubertal development will lead to primary amenorrhoea. It is defined as an absence of secondary sexual characteristics by age 14 with no menarche or normal secondary sexual characteristics but no menarche by 16 years of age.

Secondary amenorrhoea (menstrual cycles ceasing) is often caused by hormonal disturbances from the hypothalamus and the pituitary gland, from premature menopause or intrauterine scar formation. It is defined as the absence of menses for three months in a woman with previously normal menstruation or nine months for women with a history of oligomenorrhoea.

Anovulation is when the ovaries do not release an oocyte during a menstrual cycle. Therefore, ovulation does not take place. However, a woman who does not ovulate at each menstrual cycle is not necessarily going through menopause. Chronic anovulation is a common cause of infertility.

In addition to the alteration of menstrual periods and infertility, chronic anovulation can cause or exacerbate other long term problems, such as hyperandrogenism or osteopenia. It plays a central role in the multiple imbalances and dysfunctions of polycystic ovary syndrome.

During the first two years after menarche 50% of the menstrual cycles could be anovulatories.

It is in fact possible to restore ovulation using appropriate medication, and ovulation is successfully restored in approximately 90% of cases. The first step is the diagnosis of anovulation. The identification of anovulation is not easy; contrary to what is commonly believed, women undergoing anovulation still have (more or less) regular periods. In general, patients only notice that there is a problem once they have started trying to conceive.

Temperature charting is a useful way of providing early clues about anovulation, and can help gynaecologists in their diagnosis.

The main symptom of dysmenorrhea is pain concentrated in the lower abdomen or pelvis. It is also commonly felt in the right or left side of the abdomen. It may radiate to the thighs and lower back.

Symptoms often co-occurring with menstrual pain include nausea and vomiting, diarrhea or constipation, headache, dizziness, disorientation, hypersensitivity to sound, light, smell and touch, fainting, and fatigue. Symptoms of dysmenorrhea often begin immediately after ovulation and can last until the end of menstruation. This is because dysmenorrhea is often associated with changes in hormonal levels in the body that occur with ovulation. The use of certain types of birth control pills can prevent the symptoms of dysmenorrhea because they stop ovulation from occurring.

Oligomenorrhea (or oligomenorrhoea) is infrequent (or, in occasional usage, very light) menstruation. More strictly, it is menstrual periods occurring at intervals of greater than 35 days, with only four to nine periods in a year. Menstrual periods should have been regularly established before the development of infrequent flow. The duration of such events may vary.

A normal menstrual cycle is 21–35 days in duration, with bleeding lasting an average of 5 days and total blood flow between 25 and 80 mL. Menorrhagia is defined as total menstrual flow >80ml per cycle, or soaking a pad/tampon every 2 hours or less. Deviations in terms of frequency of menses, duration of menses, or volume of menses qualifies as abnormal uterine bleeding. Bleeding in between menses is also abnormal uterine bleeding and thus requires further evaluation.

Complications of Menorrhagia could also be the initial symptoms. Excessive bleeding can lead to anemia which presents as fatigue, shortness of breath, and weakness. Anemia can be diagnosed with a blood test.

Oligomenorrhea can be a result of prolactinomas (adenomas of the anterior pituitary). It may be caused by thyrotoxicosis, hormonal changes in perimenopause, Prader–Willi syndrome, and Graves disease.

"Endurance exercises such as running or swimming can affect the reproductive physiology of women athletes. Female runners, swimmers and ballet dancers menstruate infrequently in comparison to nonatheletic women of comparable age or not at all (amenorrhea). The degree of menstrual abnormality is directly proportional to the intensity of the exercise. For example, Malina et al., (1978) have shown menstrual irregularity is more common, and more severe among tennis players than among golfers" (modified by a student paper written by A. Lord)

Breastfeeding has been linked to irregularity of menstrual cycles due to hormones that delay ovulation.

Women with polycystic ovary syndrome (PCOS) are also likely to suffer from oligomenorrhea. PCOS is a condition in which excessive androgens (male sex hormones) are released by the ovaries. Women with PCOS show menstrual irregularities that range from oligomenorrhea and amenorrhea, to very heavy, irregular periods. The condition affects about 6% of premenopausal women.

Eating disorders can result in oligomenorrhea. Although menstrual disorders are most strongly associated with Anorexia nervosa, Bulimia nervosa may also result in oligomenorrhea or amenorrhea. There is some controversy regarding the mechanism for the menstrual dysregulation, since amenorrhea may sometimes precede substantial weight loss in some anorexics. Some researchers hypothesize that some as-yet unrecognized neuroendocrine phenomenon may be involved; the menstrual irregularities may be related to the biological undergirding of the disorders, rather than a result of nutritional deficiencies.

Dysmenorrhea, also known as painful periods, or menstrual cramps, is pain during menstruation. Its usual onset occurs around the time that menstruation begins. Symptoms typically last less than three days. The pain is usually in the pelvis or lower abdomen. Other symptoms may include back pain, diarrhea, or nausea.

In young women painful periods often occur without an underlying problem. In older women it is more often due to an underlying issues such as uterine fibroids, adenomyosis, or endometriosis. It is more common among those with heavy periods, irregular periods, whose periods started before twelve years of age, or who have a low body weight. A pelvic exam in those who are sexually active and ultrasound may be useful to help in diagnosis. Conditions that should be ruled out include ectopic pregnancy, pelvic inflammatory disease, interstitial cystitis, and chronic pelvic pain.

Dysmenorrhea occurs less often in those who exercise regularly and those who have children early in life. Treatment may include the use of a heating pad. Medications that may help include NSAIDs such as ibuprofen, hormonal birth control, and the IUD with progestogen. Taking vitamin B or magnesium may help. Evidence for yoga, acupuncture, and massage is insufficient. Surgery may be useful if certain underlying problems are present.

Dysmenorrhea is estimated to occur in 20% to 90% of women of reproductive age. It is the most common menstrual disorder. Typically it starts within a year of the first menstrual period. When there is no underlying cause often the pain improves with age or following having a child.

Women may notice other physical symptoms associated with their mittelschmerz, during or near ovulation. The most common sign is the appearance of fertile cervical mucus in the days leading up to ovulation. Cervical mucus is one of the primary signs used by various fertility awareness methods. Other symptoms are sometimes called "secondary fertility signs" to distinguish from the three primary signs.

- Mid-cycle or ovulatory bleeding is thought to result from the sudden drop in estrogen that occurs just before ovulation. This drop in hormones can trigger withdrawal bleeding in the same way that switching from active to placebo birth control pills does. The rise in hormones that occurs after ovulation prevents such mid-cycle spotting from becoming as heavy or long lasting as a typical menstruation. Spotting is more common in longer cycles.

- A woman's vulva may swell just prior to ovulation, especially the side on which ovulation will occur.

- One of the groin lymph nodes (on the side on which ovulation will occur) will swell to about the size of a pea, and may become tender.

Menorrhagia is a menstrual period with excessively heavy flow and falls under the larger category of abnormal uterine bleeding (AUB).

Abnormal uterine bleeding can be caused by structural abnormalities in the reproductive tract, anovulation, bleeding disorders, hormone issues (such as hypothyroidism) or cancer of the reproductive tract. Initial evaluation aims at figuring out pregnancy status, menopausal status, and the source of bleeding.

Treatment depends on the cause, severity, and interference with quality of life. Initial treatment often involve contraceptive pills. Surgery can be an effective second line treatment for those women whose symptoms are not well-controlled. Approximately 53 in 1000 women are affected by AUB.

Excessive menstruation between puberty and 19 years of age is called puberty menorrhagia. Excessive menstruation is defined as bleeding over 80 ml per menstrual period or lasting more than 7 days. The most common cause for puberty menorrhagia is dysfunctional uterine bleeding. The other reasons are idiopathic thrombocytopenic purpura, hypothyroidism, genital tuberculosis, polycystic ovarian disease, leukemia and coagulation disorders. The most common physiological reason for puberty menorrhagia is the immaturity of hypothalamic-pituitary-ovarian axis, leading to inadequate positive feedback and sustained high estrogen levels. Most patients present with anemia due to excessive blood loss.

The patient is assessed with a thorough medical history, physical examination (to look for features of anemia), gynaecological examination (to rule out local causes) and laboratory investigations (to rule out coagulopathies and malignancy). It is mandatory to exclude pregnancy. The treatment is determined based on the cause of menorrhagia. In case of puberty menorrhagia due to immaturity of hypothalamic axis, hormonal therapy is beneficial. Treatment for blood loss should be done simultaneously with iron therapy in mild to moderate blood loss and blood transfusion in severe blood loss.

Mittelschmerz is characterized by lower abdominal and pelvic pain that occurs roughly midway through a woman's menstrual cycle. The pain can appear suddenly and usually subsides within hours, although it may sometimes last two or three days. In some cases it can last up to the following cycle. In some women, the mittelschmerz is localized enough so that they can tell which of their two ovaries provided the egg in a given month. Because ovulation occurs on a random ovary each cycle, the pain may switch sides or stay on the same side from one cycle to another.

Pain and infertility are common symptoms, although 20-25% of women are asymptomatic.

Dysfunctional uterine bleeding (DUB) is abnormal genital tract bleeding based in the uterus and found in the absence of demonstrable structural or organic disease. It is usually due to hormonal disturbances: reduced levels of progesterone cause low levels of prostaglandin F2alpha and cause menorrhagia (abnormally heavy flow); increased levels of tissue plasminogen activator (TPA) (a fibrinolytic enzyme) lead to more fibrinolysis.

Diagnosis must be made by exclusion, since organic pathology must first be ruled out.

DUB can be classified as "ovulatory" or "anovulatory", depending on whether ovulation is occurring or not. It is usually a menstrual disorder, although abnormal bleeding from the uterus is possible outside menstruation.

Some sources state that the term "dysfunctional" implies a hormonal mechanism. Use of the term "abnormal uterine bleeding" is preferred in today's medicine.

A major symptom of endometriosis is recurring pelvic pain. The pain can range from mild to severe cramping or stabbing pain that occurs on both sides of the pelvis, in the lower back and rectal area, and even down the legs. The amount of pain a woman feels correlates weakly with the extent or stage (1 through 4) of endometriosis, with some women having little or no pain despite having extensive endometriosis or endometriosis with scarring, while other women may have severe pain even though they have only a few small areas of endometriosis. Symptoms of endometriosis-related pain may include:

- dysmenorrhea – painful, sometimes disabling cramps during the menstrual period; pain may get worse over time (progressive pain), also lower back pains linked to the pelvis

- chronic pelvic pain – typically accompanied by lower back pain or abdominal pain

- dyspareunia – painful sex

- dysuria – urinary urgency, frequency, and sometimes painful voiding

Compared with women with superficial endometriosis, those with deep disease appear to be more likely to report shooting rectal pain and a sense of their insides being pulled down. Individual pain areas and pain intensity appear to be unrelated to the surgical diagnosis, and the area of pain unrelated to area of endometriosis.

There are multiple causes of pain. Endometriosis lesions react to hormonal stimulation and may "bleed" at the time of menstruation. The blood accumulates locally if it is not cleared shortly by the immune, circulatory, and lymphatic system. This may further lead to swelling, which triggers inflammation with the activation of cytokines, which results in pain. Another source of pain is the organ dislocation that arises from adhesion binding internal organs to each other. The ovaries, the uterus, the oviducts, the peritoneum, and the bladder can be bound together. Pain triggered in this way can last throughout the menstrual cycle, not just during menstrual periods.

Also, endometriotic lesions can develop their own nerve supply, thereby creating a direct and two-way interaction between lesions and the central nervous system, potentially producing a variety of individual differences in pain that can, in some women, become independent of the disease itself. Nerve fibres and blood vessels are thought to grow into endometriosis lesions by a process known as Neuroangiogenesis.

10% of cases occur in women who are ovulating, but progesterone secretion is prolonged because estrogen levels are low. This causes irregular shedding of the uterine lining and break-through bleeding. Some evidence has associated Ovulatory DUB with more fragile blood vessels in the uterus.

It may represent a possible endocrine dysfunction, resulting in menorrhagia or metrorrhagia.

Mid-cycle bleeding may indicate a transient estrogen decline, while late-cycle bleeding may indicate progesterone deficiency.

Common signs and symptoms of PCOS include the following:

- Menstrual disorders: PCOS mostly produces oligomenorrhea (fewer than nine menstrual periods in a year) or amenorrhea (no menstrual periods for three or more consecutive months), but other types of menstrual disorders may also occur.

- Infertility: This generally results directly from chronic anovulation (lack of ovulation).

- High levels of masculinizing hormones: Known as hyperandrogenism, the most common signs are acne and hirsutism (male pattern of hair growth, such as on the chin or chest), but it may produce hypermenorrhea (heavy and prolonged menstrual periods), androgenic alopecia (increased hair thinning or diffuse hair loss), or other symptoms. Approximately three-quarters of women with PCOS (by the diagnostic criteria of NIH/NICHD 1990) have evidence of hyperandrogenemia.

- Metabolic syndrome: This appears as a tendency towards central obesity and other symptoms associated with insulin resistance. Serum insulin, insulin resistance, and homocysteine levels are higher in women with PCOS.

Asians affected by PCOS are less likely to develop hirsutism than those of other ethnic backgrounds.

Not everyone with PCOS has polycystic ovaries (PCO), nor does everyone with ovarian cysts have PCOS; although a pelvic ultrasound is a major diagnostic tool, it is not the only one. The diagnosis is straightforward using the Rotterdam criteria, even when the syndrome is associated with a wide range of symptoms.