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.

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.

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.

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.

Polycystic ovary syndrome (PCOS) is a set of symptoms due to elevated androgens (male hormones) in women. Signs and symptoms of PCOS include irregular or no menstrual periods, heavy periods, excess body and facial hair, acne, pelvic pain, difficulty getting pregnant, and patches of thick, darker, velvety skin. Associated conditions include type 2 diabetes, obesity, obstructive sleep apnea, heart disease, mood disorders, and endometrial cancer.

PCOS is due to a combination of genetic and environmental factors. Risk factors include obesity, not enough physical exercise, and a family history of someone with the condition. Diagnosis is based on two of the following three findings: no ovulation, high androgen levels, and ovarian cysts. Cysts may be detectable by ultrasound. Other conditions that produce similar symptoms include adrenal hyperplasia, hypothyroidism, and hyperprolactinemia.

PCOS has no cure. Treatment may involve lifestyle changes such as weight loss and exercise. Birth control pills may help with improving the regularity of periods, excess hair growth, and acne. Metformin and anti-androgens may also help. Other typical acne treatments and hair removal techniques may be used. Efforts to improve fertility include weight loss, clomiphene, or metformin. In vitro fertilization is used by some in whom other measures are not effective.

PCOS is the most common endocrine disorder among women between the ages of 18 and 44. It affects approximately 2% to 20% of this age group depending on how it is defined. It is one of the leading causes of poor fertility. The earliest known description of what is now recognized as PCOS dates from 1721 in Italy.

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.

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.

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.

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.

"Demographers tend to define infertility as childlessness in a population of women of reproductive age," whereas "the epidemiological definition refers to "trying for" or "time to" a pregnancy, generally in a population of women exposed to" a probability of conception. Currently, female fertility normally peaks at age 24 and diminishes after 30, with pregnancy occurring rarely after age 50. A female is most fertile within 24 hours of ovulation. Male fertility peaks usually at age 25 and declines after age 40. The time needed to pass (during which the couple tries to conceive) for that couple to be diagnosed with infertility differs between different jurisdictions. Existing definitions of infertility lack uniformity, rendering comparisons in prevalence between countries or over time problematic. Therefore, data estimating the prevalence of infertility cited by various sources differs significantly. A couple that tries unsuccessfully to have a child after a certain period of time (often a short period, but definitions vary) is sometimes said to be subfertile, meaning less fertile than a typical couple. Both infertility and subfertility are defined as the inability to conceive after a certain period of time (the length of which vary), so often the two terms overlap.

The following causes of infertility may only be found in females.

For a woman to conceive, certain things have to happen: vaginal intercourse must take place around the time when an egg is released from her ovary; the system that produces eggs has to be working at optimum levels; and her hormones must be balanced.

For women, problems with fertilisation arise mainly from either structural problems in the Fallopian tube or uterus or problems releasing eggs. Infertility may be caused by blockage of the Fallopian tube due to malformations, infections such as chlamydia and/or scar tissue. For example, endometriosis can cause infertility with the growth of endometrial tissue in the Fallopian tubes and/or around the ovaries. Endometriosis is usually more common in women in their mid-twenties and older, especially when postponed childbirth has taken place.

Another major cause of infertility in women may be the inability to ovulate. Malformation of the eggs themselves may complicate conception. For example, polycystic ovarian syndrome is when the eggs only partially developed within the ovary and there is an excess of male hormones. Some women are infertile because their ovaries do not mature and release eggs. In this case synthetic FSH by injection or Clomid (Clomiphene citrate) via a pill can be given to stimulate follicles to mature in the ovaries.

Other factors that can affect a woman's chances of conceiving include being overweight or underweight, or her age as female fertility declines after the age of 30.

Sometimes it can be a combination of factors, and sometimes a clear cause is never established.

Common causes of infertility of females include:

- ovulation problems (e.g. polycystic ovarian syndrome, PCOS, the leading reason why women present to fertility clinics due to anovulatory infertility.)

- tubal blockage

- pelvic inflammatory disease caused by infections like tuberculosis

- age-related factors

- uterine problems

- previous tubal ligation

- endometriosis

- advanced maternal age

- immune infertility

The symptoms of Leydig cell hypoplasia include pseudohermaphroditism (i.e., feminized, ambiguous, or relatively mildly underdeveloped (e.g., micropenis, severe hypospadias, and/or cryptorchidism (undescended testes)) external genitalia), a female gender identity or gender variance, hypergonadotropic hypogonadism (hypogonadism despite high levels of gonadotropins), delayed, impaired, or fully absent puberty with an associated reduction in or complete lack of development of secondary sexual characteristics (sexual infantilism), impaired fertility or complete sterility, tall stature (due to delayed epiphyseal closure), eunuchoid skeletal proportions, delayed or absent bone maturation, and osteoporosis.

Leydig cell hypoplasia (or aplasia) (LCH), also known as Leydig cell agenesis, is a rare autosomal recessive genetic and endocrine syndrome affecting an estimated 1 in 1,000,000 genetic males. It is characterized by an inability of the body to respond to luteinizing hormone (LH), a gonadotropin which is normally responsible for signaling Leydig cells of the testicles to produce testosterone and other androgen sex hormones. The condition manifests itself as pseudohermaphroditism (partially or fully underdeveloped genitalia), hypergonadotropic hypogonadism (decreased or lack of production of sex steroids by the gonads despite high circulating levels of gonadotropins), reduced or absent puberty (lack of development of secondary sexual characteristics, resulting in sexual infantilism if left untreated), and infertility.

Leydig cell hypoplasia does not occur in biological females as they do not have either Leydig cells or testicles. However, the cause of the condition in males, luteinizing hormone insensitivity, does affect females, and because LH plays a role in the female reproductive system, it can result in primary amenorrhea or oligomenorrhea (absent or reduced menstruation), infertility due to anovulation, and ovarian cysts.

A related condition is follicle-stimulating hormone (FSH) insensitivity, which presents with similar symptoms to those of Leydig cell hypoplasia but with the symptoms in the respective sexes reversed (i.e., hypogonadism and sexual infantilism in females and merely problems with fertility in males). Despite their similar causes, FSH insensitivity is considerably less common in comparison to LH insensitivity.

Mutations that result in some residual 21-hydroxylase activity cause milder disease, traditionally termed simple virilizing CAH (SVCAH). In these children the mineralocorticoid deficiency is less significant and salt-wasting does not occur. However, genital ambiguities are possible.

Virilization of genetically female (XX) infants usually produces obvious genital ambiguity. Inside the pelvis, the ovaries are normal and since they have not been exposed to testicular antimullerian hormone (MIF), the uterus, fallopian tubes, upper vagina, and other mullerian structures are normally formed as well. However, the high levels of testosterone in the blood can enlarge the phallus, partially or completely close the vaginal opening, enclose the urethral groove so that it opens at the base of the phallus, on the shaft or even at the tip like a boy. Testosterone can cause the labial skin to become as thin and rugated as a scrotum, but cannot produce palpable gonads (i.e., testes) in the folds.

Thus, depending on the severity of hyperandrogenism, a female infant can be mildly affected, obviously ambiguous, or so severely virilized as to appear to be a male. Andrea Prader devised the following Prader scale as a way of describing the degree of virilization.

- An infant at stage 1 has a mildly large clitoris and slightly reduced vaginal opening size. This degree may go unnoticed or may be simply assumed to be within normal variation.

- Stages 2 and 3 represent progressively more severe degrees of virilization. The genitalia are obviously abnormal to the eye, with a phallus intermediate in size and a small vaginal opening.

- Stage 4 looks more male than female, with an empty scrotum and a phallus the size of a normal penis, but not quite free enough of the perineum to be pulled onto the abdomen toward the umbilicus (i.e., what is termed a chordee in a male). The single small urethral/vaginal opening at the base or on the shaft of the phallus would be considered a hypospadias in a male. X-rays taken after dye injection into this opening reveal the internal connection with the upper vagina and uterus. This common opening can predispose to urinary obstruction and infection.

- Stage 5 denotes complete male virilization, with a normally formed penis with the urethral opening at or near the tip. The scrotum is normally formed but empty. The internal pelvic organs include normal ovaries and uterus, and the vagina connects internally with the urethra as in Stage 4. These infants are not visibly ambiguous, and are usually assumed to be ordinary boys with undescended testes. In most cases, the diagnosis of CAH is not suspected until signs of salt-wasting develop a week later.

When the genitalia are determined to be ambiguous at birth, CAH is one of the leading diagnostic possibilities. Evaluation reveals the presence of a uterus, extreme elevation of 17OHP, levels of testosterone approaching or exceeding the male range but low AMH levels. The karyotype is that of an ordinary female: 46,XX. With this information, the diagnosis of CAH is readily made and female sex confirmed.

Evaluation of ambiguous genitalia is described in detail elsewhere. In most cases it is possible to confirm and assign female sex within 12–36 hours of birth. The exception are the rare, completely virilized genetic females (Prader stage 5), who present the most challenging assignment and surgery dilemmas, discussed below.

When the degree of ambiguity is obvious, corrective surgery is usually offered and performed. As reconstructive surgery on infant genitalia has become a focus of controversy, the issues are described in more detail below.

Menstruation occurs typically monthly, lasts 3–7 days, and involves up to 80 ml blood. Bleeding in excess of this norm in a nonpregnant woman constitutes gynecologic hemorrhage. In addition, early pregnancy bleeding has sometimes been included as gynecologic hemorrhage, namely bleeding from a miscarriage or an ectopic pregnancy, while it actually represents obstetrical bleeding. However, from a practical view, early pregnancy bleeding is usually handled like a gynecological hemorrhage.

The symptoms of CAH vary depending upon the form of CAH and the sex of the patient. Symptoms can include:

Due to inadequate mineralocorticoids:

- vomiting due to salt-wasting leading to dehydration and death

Due to excess androgens:

- functional and average sized penis in cases involving extreme virilization (but no sperm)

- ambiguous genitalia, in some females, such that it can be initially difficult to identify external genitalia as "male" or "female".

- early pubic hair and rapid growth in childhood

- precocious puberty or failure of puberty to occur (sexual infantilism: absent or delayed puberty)

- excessive facial hair, virilization, and/or menstrual irregularity in adolescence

- infertility due to anovulation

- clitoromegaly, enlarged clitoris and shallow vagina

Due to insufficient androgens and estrogens:

- Undervirilization in XY males, which can result in apparently female external genitalia

- In females, hypogonadism can cause sexual infantilism or abnormal pubertal development, infertility, and other reproductive system abnormalities

Gynecologic hemorrhage represents excessive bleeding of the female reproductive system. Such bleeding could be visible or external, namely bleeding from the vagina, or it could be internal into the pelvic cavity or form a hematoma. Normal menstruation is not considered a gynecologic hemorrhage, as it is not excessive. Hemorrhage associated with a pregnant state or during delivery is an obstetrical hemorrhage.

Congenital adrenal hyperplasia (CAH) are any of several autosomal recessive diseases resulting from mutations of genes for enzymes mediating the biochemical steps of production of mineralocorticoids, glucocorticoids or sex steroids from cholesterol by the adrenal glands (steroidogenesis).

Most of these conditions involve excessive or deficient production of sex steroids and can alter development of primary or secondary sex characteristics in some affected infants, children, or adults.

Milder cases of lipoid CAH have been described that arise from less severe mutations that compromise but do not eliminate the ability of StAR to instigate steroid production. In these cases, mineralocorticoid deficiency emerges up to several years after birth. Sex steroid production may be sufficient to allow for normal sexual development as well and even fertility.

These nonclassic forms of the disorder are sometimes diagnosed as familial glucocorticoid deficiency type 3.

Most infants born with lipoid CAH have had genitalia female enough that no disease was suspected at birth. Because the adrenal zona glomerulosa is undifferentiated and inactive before delivery, it is undamaged at birth and can make aldosterone for a while, so the eventual salt-wasting crisis develops more gradually and variably than with severe 21-hydroxylase-deficient CAH.

Most come to medical attention between 2 weeks and 3 months of age, when after a period of poor weight gain and vomiting, they were found to be dehydrated, with severe hyponatremia, hyperkalemia, and metabolic acidosis ("Addisonian or adrenal crisis"). Renin but not aldosterone is elevated. Many infants born with this condition died before a method for diagnosis was recognized for proper treatment to begin. In some cases, the condition is more mild with signs and symptoms of mineralocorticoid and glucocorticoid deficiency appearing after months or even years (late onset).

The majority of Leydig cell tumors are found in males, usually at 5–10 years of age or in middle adulthood (30–60 years). Children typically present with precocious puberty. Due to excess testosterone secreted by the tumour, one-third of female patients present with a recent history of progressive masculinization. Masculinization is preceded by anovulation, oligomenorrhea, amenorrhea and "defeminization". Additional signs include acne and hirsutism, voice deepening, clitoromegaly, temporal hair recession, and an increase in musculature. Serum testosterone level is high.

In men testicular swelling is the most common presenting feature. Other symptoms depend on their age and the type of tumour. If it is secreting androgens the tumour is usually asymptomatic, but can cause precocious puberty in pre-pubertal boys. If the tumour secretes oestrogens it can cause feminisation in young boys. In adults, this causes a number of problems including gynaecomastia, erectile dysfunction, infertility, feminine hair distribution, gonadogenital atrophy, and a loss of libido.

Presence of an ovarian tumour plus hormonal disturbances suggests a Leydig cell tumour, granulosa cell tumour or thecoma. However, hormonal disturbances, in Leydig tumours, is present in only 2/3 of cases. Testicular Leydig cell tumours can be detected sonographically, ultrasound examinations may be ordered in the event of a palpable scrotal lump, however incidental identification of these lesions is also possible.

A conclusive diagnosis is made via histology, as part of a pathology report made during or after surgery. Reinke crystals are classically found in these tumours and help confirm the diagnosis, although they are seen in less than half of all Leydig cell tumours. See also Sex cord-stromal tumour. Immunohistochemical markers of Leydig cell tumours include inhibin-alpha, calretinin, and melan-A.

Due to excess testosterone secreted by the tumour, one-third of female patients present with a recent history of progressive masculinization. Masculinization is preceded by anovulation, oligomenorrhoea, amenorrhoea and defeminization. Additional signs include acne and hirsutism, voice deepening, clitoromegaly, temporal hair recession, and an increase in musculature. Serum testosterone level is high.