Bleeding before the expected time of menarche could be a sign of precocious puberty. Other possible causes include the presence of a foreign body in the vagina, molestation, vaginal infection (vaginitis), and rarely, a tumor.

Most unusual bleeding or irregular bleeding (metrorrhagia) in premenopausal women is caused by changes in the hormonal balance of the body. These changes are not pathological. Exceptionally heavy bleeding during menstruation is termed "menorrhagia" or "hypermenorrhea", while light bleeding is called "hypomenorrhea". Women on hormonal contraceptives can experience breakthrough bleeding and/or withdrawal bleeding. Withdrawal bleeding occurs when a hormonal contraceptive or other hormonal intake is discontinued.

There are pathological causes of unusual vaginal bleeding as well. Dysfunctional uterine bleeding is a common cause of menorrhagia and irregular bleeding. It is due to a hormonal imbalance, and symptoms can be managed by use of hormonal contraception (although hormonal contraception does not treat the underlying cause of the imbalance). If it is due to polycystic ovary syndrome, weight loss may help, and infertility may respond to clomifene citrate. Uterine fibroids (leiomyoma) are benign tumors of the uterus that cause bleeding and pelvic pain in approximately 30% of affected women. Adenomyosis, a condition in which the endometrial glands grow into the uterine muscle, can cause dysmenorrhea and menorrhagia. Cervical cancer may occur at premenopausal age, and often presents with "contact bleeding" (e.g. after sexual intercourse). Uterine cancer leads to irregular and often prolonged bleeding. In recently pregnant women who have delivered or who have had a miscarriage, vaginal bleeding may be a sign of endometritis or retained products of conception.

Patients can have pain secondary to uterine contractions, uterine tetany or localized uterine tenderness. Signs can also be due to abruptio placentae including uterine hypertonus, fetal distress, fetal death, and rarely, hypovolaemic shock (shock secondary to severe blood loss). The uterus may adopt a bluish/purplish, mottled appearance due to extravasation of blood into uterine muscle.

It is often characterized by a decrease in flow and duration of bleeding (absence of menstrual bleeding, little menstrual bleeding, or infrequent menstrual bleeding) and become infertile. Menstrual anomalies are often but not always correlated with severity: adhesions restricted to only the cervix or lower uterus may block menstruation. Pain during menstruation and ovulation is sometimes experienced and can be attributed to blockages.

It has been reported that 88% of AS cases occur after a D&C is performed on a recently pregnant uterus, following a missed or incomplete miscarriage, birth, or during an elective termination (abortion) to remove retained products of conception.

Adenomyosis can vary widely in the type and severity of symptoms that it causes, ranging from being entirely asymptomatic 33% of the time to being a severe and debilitating condition in some cases. Women with adenomyosis typically first report symptoms when they are between 40 and 50, but symptoms can occur in younger women.

Symptoms and the estimated percent affected may include:

- Chronic pelvic pain (77%)

- Heavy menstrual bleeding (40-60%), which is more common with in women with deeper adenomyosis. Blood loss may be significant enough to cause anemia, with associated symptoms of fatigue, dizziness, and moodiness.

- Abnormal uterine bleeding

- Painful cramping menstruation (15-30%)

- Painful vaginal intercourse (7%)

- A 'bearing' down feeling

- Pressure on bladder

- Dragging sensation down thighs and legs

Clinical signs of adenomyosis may include:

- Uterine enlargement (30%), which in turn can lead to symptoms of pelvic fullness.

- Tender uterus

- Infertility or sub-fertility (11-12%) - In addition, adenomyosis is associated with an increased incidence of preterm labour and premature rupture of membranes.

Women with adenomyosis are also more likely to have other uterine conditions, including:

- Uterine fibroids (50%)

- Endometriosis (11%)

- Endometrial polyp (7%)

Uterine hyperstimulation or hypertonic uterine dysfunction is a potential complication of labor induction. It is defined as either a series of single contractions lasting 2 minutes or more OR a contraction frequency of five or more in 10 minutes. Uterine hyperstimulation may result in fetal heart rate abnormalities, uterine rupture, or placental abruption. It is usually treated by administering terbutaline.

A Cervical pregnancy is an ectopic pregnancy that has implanted in the uterine endocervix. Such a pregnancy typically aborts within the first trimester, however, if it is implanted closer to the uterine cavity - a so-called cervico-isthmic pregnancy - it may continue longer. Placental removal in a cervical pregnancy may result in major hemorrhage.

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 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.

An interstitial pregnancy is a uterine but ectopic pregnancy; the pregnancy is located outside the uterine cavity in that part of the fallopian tube that penetrates the muscular layer of the uterus. The term cornual pregnancy is sometimes used as a synonym, but remains ambiguous as it is also applied to indicate the presence of a pregnancy located within the cavity in one of the two upper "horns" of a bicornuate uterus. Interstitial pregnancies have a higher mortality than ectopics in general.

Symptoms of a rupture may be initially quite subtle. An old cesarean scar may undergo dehiscence; but with further labor the woman may experience abdominal pain and vaginal bleeding, though these signs are difficult to distinguish from normal labor. Often a deterioration of the fetal heart rate is a leading sign, but the cardinal sign of uterine rupture is loss of fetal station on manual vaginal exam. Intra-abdominal bleeding can lead to hypovolemic shock and death. Although the associated maternal mortality is now less than one percent, the fetal mortality rate is between two and six percent when rupture occurs in the hospital.

In pregnancy uterine rupture may cause a viable abdominal pregnancy. This is what accounts for most abdominal pregnancy births.

- Abdominal pain and tenderness. The pain may not be severe; it may occur suddenly at the peak of a contraction. The woman may describe a feeling that something "gave way" or "ripped."

- Chest pain, pain between the scapulae, or pain on inspiration—Pain occurs because of the irritation of blood below the woman's diaphragm

- Hypovolemic shock caused by haemorrhage— Falling blood pressure, tachycardia, tachypnea, pallor, cool and clammy skin, and anxiety. The fall in blood pressure is often a late sign of haemorrhage

- Signs associated with fetal oxygenation, such as late deceleration, reduced variability, tachycardia, and bradycardia

- Absent fetal heart sounds with a large disruption of the placenta; absent fetal heart activity by ultrasound examination

- Cessation of uterine contractions

- Palpation of the fetus outside the uterus (usually occurs only with a large, complete rupture). The fetus is likely to be dead at this point.

- Signs of an abdominal pregnancy

- Post-term pregnancy

The diagnosis is made in asymptomatic pregnant women either by inspection seeing a bluish discolored cervix or, more commonly, by obstetric ultrasonography. A typical non-specific symptom is vaginal bleeding during pregnancy. Ultrasound will show the location of the gestational sac in the cervix, while the uterine cavity is "empty". Cervical pregnancy can be confused with a miscarriage when pregnancy tissue is passing through the cervix.

Histologically the diagnosis has been made by Rubin’s criteria on the surgical specimen: cervical glands are opposite the trophoblastic tissue, the trophoblastic attachment is below the entrance of the uterine vessels to the uterus or the anterior peritoneal reflection, and fetal elements are absent from the uterine corpus. As many pregnancies today are diagnosed early and no hysterectomy is performed, Rubin's criteria can often not be applied.

Uterine atony is a loss of tone in the uterine musculature. Normally, contraction of the uterine muscles during labor compresses the blood vessels and reduces flow, thereby increasing the likelihood of coagulation and preventing hemorrhage. A lack of uterine muscle contraction, however, can lead to an acute hemorrhage, as the uterine blood vessels are not sufficiently compressed. Clinically, 75-80% of postpartum hemorrhages are due to uterine atony.

The most obvious symptom of open pyometra is a discharge of pus from the vulva in a female that has recently been in heat. However, symptoms of closed pyometra are less obvious. Symptoms of both types include vomiting, loss of appetite, depression, and increased drinking and urinating. Fever is seen in less than a third of female dogs with pyometra. Closed pyometra is a more serious condition than open pyometra not only because there is no outlet for the infection, but also because a diagnosis of closed pyometra can easily be missed due to its insidious nature. Bloodwork may show dehydration and/or increased white blood cell count. X-rays will show an enlarged uterus, and ultrasound will confirm the presence of a fluid filled uterus.

Couvelaire uterus (also known as uteroplacental apoplexy) is a life-threatening condition in which loosening of the placenta (abruptio placentae) causes bleeding that penetrates into the uterine myometrium forcing its way into the peritoneal cavity.

Various classification systems were developed to describe Asherman’s syndrome (citations to be added), some taking into account the amount of functioning residual endometrium, menstrual pattern, obstetric history and other factors which are thought to play a role in determining the prognoses. With the advent of techniques which allow visualization of the uterus, classification systems were developed to take into account the location and severity of adhesions inside the uterus. This is useful as mild cases with adhesions restricted to the cervix may present with amenorrhea and infertility, showing that symptoms alone do not necessarily reflect severity. Other patients may have no adhesions but amenorrhea and infertility due to a sclerotic atrophic endometrium. The latter form has the worst prognosis.

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.

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.

Hematometra typically presents as cyclic, cramping pain in the midline of the pelvis or lower abdomen. Patients may also report urinary frequency and urinary retention. Premenopausal women with hematometra often experience abnormal vaginal bleeding, including dysmenorrhea (pain during menstruation) or amenorrhea (lack of menstruation), while postmenopausal women are more likely to be asymptomatic. Due to the accumulation of blood in the uterus, patients may develop low blood pressure or a vasovagal response. When palpated, the uterus will typically feel firm and enlarged.

Menometrorrhagia is a condition in which prolonged or excessive uterine bleeding occurs irregularly and more frequently than normal. It is thus a combination of metrorrhagia and menorrhagia.

Adenomyosis is a gynecologic medical condition characterized by the abnormal presence of endometrial tissue (the inner lining of the uterus) within the myometrium (the thick, muscular layer of the uterus). In contrast, when endometrial tissue is present entirely outside the uterus, it represents a similar but distinct medical condition called endometriosis. The two conditions are found together in many cases, but often occur independently. Before being recognized as its own condition, adenomyosis used to be called "endometriosis interna". Additionally, the less-commonly used term "adenomyometritis" is a more specific name for the condition, specifying involvement of the uterus.

The condition is typically found in women between the ages of 35 and 50 but can also be present in younger women. Patients with adenomyosis often present with painful and/or profuse menses (dysmenorrhea & menorrhagia, respectively). Other possible symptoms are pain during sexual intercourse, chronic pelvic pain and irritation of the urinary bladder.

In adenomyosis, "basal" endometrium penetrates into hyperplastic myometrial fibers. Therefore, unlike functional layer, basal layer does not undergo typical cyclic changes with menstrual cycle.

Adenomyosis may involve the uterus focally, creating an adenomyoma. With diffuse involvement, the uterus becomes bulky and heavier.

Abnormal uterine bleeding is a general category that includes any bleeding from menstrual or nonmenstrual causes. Hypomenorrhea is abnormally light menstrual periods. Menorrhagia (meno = month, rrhagia = excessive flow/discharge) is an abnormally heavy and prolonged menstrual period. Metrorrhagia is bleeding at irregular times, especially outside the expected intervals of the menstrual cycle. If there is excessive menstrual and uterine bleeding other than that caused by menstruation, menometrorrhagia (meno = prolonged, metro = uterine, rrhagia = excessive flow/discharge) may be diagnosed. Causes may be due to abnormal blood clotting, disruption of normal hormonal regulation of periods or disorders of the endometrial lining of the uterus. Depending upon the cause, it may be associated with abnormally painful periods.

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).

The initial workup includes exclusion of pregnancy and cancer, by performing a pregnancy test, a pelvic exam and a gynecologic ultrasound. Further workup depends on outcomes of the preceding tests and may include hydrosonography, hysteroscopy, endometrial biopsy, and magnetic resonance imaging.

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.