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.

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.

Secondary amenorrhea's most common and most easily diagnosable causes are pregnancy, thyroid disease, and hyperprolactinemia. A pregnancy test is a common first step for diagnosis. Hyperprolactinemia, characterized by high levels of the hormone prolactin, is often associated with a pituitary tumor. A dopamine agonist can often help relieve symptoms. The subsiding of the causal syndrome is usually enough to restore menses after a few months. Secondary amenorrhea may also be caused by outflow tract obstruction, often related to Asherman's Syndrome. Polycystic ovary syndrome can cause secondary amenorrhea, although the link between the two is not well understood. Ovarian failure related to early onset menopause can cause secondary amenorrhea, and although the condition can usually be treated, it is not always reversible. Secondary amenorrhea is also caused by stress, extreme weight loss, or excessive exercise. Young athletes are particularly vulnerable, although normal menses usually return with healthy body weight. Causes of secondary amenorrhea can also result in primary amenorrhea, especially if present before onset of menarche.

Secondary amenorrhea is also caused by stress, extreme weight loss, or excessive exercise. Young athletes are particularly vulnerable, although normal menses usually return with healthy body weight. Causes of secondary amenorrhea can also result in primary amenorrhea, especially if present before onset of menarche.

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).

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.

For most women, alteration of menstrual periods is the principal indication of chronic anovulation. Ovulatory menstrual periods tend to be regular and predictable in terms of cycle length, duration and heaviness of bleeding, and other symptoms. Ovulatory periods are often accompanied by midcycle symptoms such as mittelschmerz or premenstrual symptoms. In contrast, 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). Mittelschmerz and premenstrual symptoms tend to be absent or reduced when a woman is anovulatory.

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.

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.

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.

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.

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.

In women, a high blood level of prolactin often causes hypoestrogenism with anovulatory infertility and a decrease in menstruation. In some women, menstruation may disappear altogether (amenorrhoea). In others, menstruation may become irregular or menstrual flow may change. Women who are not pregnant or nursing may begin producing breast milk. Some women may experience a loss of libido (interest in sex) and breast pain, especially when prolactin levels begin to rise for the first time, as the hormone promotes tissue changes in the breast. Intercourse may become difficult or painful because of vaginal dryness.

In men, the most common symptoms of hyperprolactinaemia are decreased libido, sexual dysfunction (in both men and women), erectile dysfunction, infertility, and gynecomastia. Because men have no reliable indicator such as menstruation to signal a problem, many men with hyperprolactinaemia being caused by a pituitary adenoma may delay going to the doctor until they have headaches or eye problems caused by the enlarged pituitary pressing against the adjacent optic chiasm. They may not recognize a gradual loss of sexual function or libido. Only after treatment do some men realize they had a problem with sexual function.

Because of hypoestrogenism and hypoandrogenism, hyperprolactinaemia can lead to osteoporosis.

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.

Exercise amenorrhoea is a medical condition in which women involved in heavy exercise experience absence of menstruation of varying periods of time. It occurs because of neuroendocrine dysfunction and is usually reversible . Exercise amenorrhoea is a component of female athlete triad.

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.

Exercise induced amenorrhoea occurs in 5-25% of athletes and 1.8% of the general population. The incidence is higher in marathon runners and is more frequent in women who weigh less and were slightly younger . Exercise amenorrhoea has also been reported in ballet dancers, cyclists, swimmers and those involved in non-weight bearing sports .

Women with hypogonadism do not begin menstruating and it may affect their height and breast development. Onset in women after puberty causes cessation of menstruation, lowered libido, loss of body hair and hot flashes. In boys it causes impaired muscle and beard development and reduced height. In men it can cause reduced body hair and beard, enlarged breasts, loss of muscle, and sexual difficulties. A brain tumor (central hypogonadism) may involve headaches, impaired vision, milky discharge from the breast and symptoms caused by other hormone problems.

Studies indicate that breast development in girls and the appearance of pubic hair in girls and boys are starting earlier than in previous generations. As a result, "early puberty" in children, particularly girls, as young as 9 and 10 is no longer considered abnormal, although it may be upsetting to parents and can be harmful to children who mature physically at a time when they are immature mentally.

No age reliably separates normal from abnormal processes in children, but the following age thresholds for evaluation are thought to minimize the risk of missing a significant medical problem:

- Breast development in boys before appearance of pubic hair or testicular enlargement,

- Pubic hair or genital enlargement (gonadarche) in boys with onset before 9.5 years,

- Pubic hair (pubarche) before 8 or breast development (thelarche) in girls with onset before 7 years,

- Menstruation (menarche) in girls before 10 years.

Medical evaluation is sometimes necessary to recognize the few children with serious conditions from the majority who have entered puberty early but are still medically normal. Early sexual development warrants evaluation because it may:

- induce early bone maturation and reduce eventual adult height,

- indicate the presence of a tumour or other serious problem,

- cause the child, particularly a girl, to become an object of adult sexual interest.

The symptoms of hypogonadotrophic hypogonadism, a subtype of hypogonadism, include late, incomplete or lack of development at puberty, and sometimes short stature or the inability to smell; in females, a lack of breasts and menstrual periods, and in males a lack of sexual development, e.g., facial hair, penis and testes enlargement, deepening voice.

Hyperandrogenism, especially high levels of testosterone, can cause serious adverse effects on women’s bodies if left untreated. High testosterone levels have been seen to be associated with obesity, hypertension, amenorrhea(stop of menstrual cycles), and ovulatory dysfunction, which can lead to infertility. The more prominent signs of hyperandrogenism are hirsutism (unwanted growth of hair especially in the abdominal region and places on the back), acne after adolescence, deepening of voice, and alopecia(balding). Hyperandrogenism has also been seen to cause individuals to have a high tolerance to insulin, which can lead to type two diabetes, and dyslipidemia, such as high cholesterol. These effects have also been seen to have a large psychological impact on the individual, sometimes often leading to societal anxiety and depression, especially in adolescent girls and young women. Paired with obesity and hirsutism, it can cause the individual to have low self-esteem, and a poor view of oneself.

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.

Hyperandrogenism affects 5-10% of females of reproductive age. Hyperandrogenism can affect both males and females, but is more noticeable in females due to the fact that elevated levels of androgens in females often facilitates virilization. Due to the fact that hyperandrogenism is characterized by the elevation of male sex hormone levels, symptoms of hyperandrogenism in men are often negligible. Hyperandrogenism in females is typically diagnosed in late adolescence with a medical evaluation. The medical evaluation tends to consist of a pelvic exam, observation of external symptoms, and a blood test measuring androgen levels.

Hyperprolactinaemia or hyperprolactinemia is the presence of abnormally high levels of prolactin in the blood. Normal levels are less than 500 mIU/L [20 ng/mL or µg/L] for women, and less than 450 mIU/L for men.

Prolactin is a peptide hormone produced by the anterior pituitary gland that is primarily associated with lactation and plays a vital role in breast development during pregnancy. Hyperprolactinaemia may cause galactorrhea (production and spontaneous flow of breast milk) and disruptions in the normal menstrual period in women and hypogonadism, infertility and erectile dysfunction in men.

Hyperprolactinaemia can also be a part of normal body changes during pregnancy and breastfeeding. It can also be caused by diseases affecting the hypothalamus and pituitary gland. It can also be caused by disruption of the normal regulation of prolactin levels by drugs, medicinal herbs and heavy metals inside the body. Hyperprolactinaemia may also be the result of disease of other organs such as the liver, kidneys, ovaries and thyroid.

If the cause can be traced to the hypothalamus or pituitary, the cause is considered central. Other names for this type are "complete" or "true precocious" puberty.

Causes of central precocious puberty can include:

- damage to the inhibitory system of the brain (due to infection, trauma, or irradiation),

- hypothalamic hamartoma produces pulsatile gonadotropin-releasing hormone (GnRH),

- Langerhans cell histiocytosis, or

- McCune–Albright syndrome.

Central precocious puberty can be caused by intracranial neoplasm, infection (most commonly central nervous system tuberculosis especially in developing countries), trauma, hydrocephalus, and Angelman syndrome. Precocious puberty is associated with advancement in bone age, which leads to early fusion of epiphyses, thus resulting in reduced final height and short stature.

Precocious puberty can make a child fertile when very young, with the youngest mother on record being Lina Medina, who gave birth at the age of 5 years, 7 months and 17 days, in one report and at 6 years 5 months in another.

"Central precocious puberty (CPP) was reported in some patients with suprasellar arachnoid cysts (SAC), and SCFE (slipped capital femoral epiphysis) occurs in patients with CPP because of rapid growth and changes of growth hormone secretion."

If no cause can be identified, it is considered idiopathic or constitutional.