Ovulation refers to the release of an egg during menstruation in females.

Part of the ovary called the ovarian follicle discharges an egg. The egg is also known as an ovum, oocyte, or female gamete. It is only released on reaching maturity.

After release, the egg travels down the fallopian tube, where it may be met by a sperm and become fertilized.

Ovulation and hormonal release during the menstrual cycle are controlled by a part of the brain called the hypothalamus. It sends signals instructing the anterior lobe and pituitary gland to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

It is useful to know when ovulation is likely to occur, as a woman is most fertile during this time, and to conceive.

There are several indications that a woman is ovulating.

During ovulation, the cervical mucus increases in volume and becomes thicker due to increased estrogen levels. The cervical mucus is sometimes at a woman's most fertile point.

There may also be a slight increase in body temperature. This is driven by the hormone progesterone, which is secreted when an egg is released. Women are generally most fertile for before the temperature reaches its maximum.

A basal thermometer can be used to track the subtle temperature increase. These can be purchased online or at most drug stores.

Some women feel a mild ache or pang of pain in the lower abdomen. This is called Mittelschmerz pain. It may last between a few minutes and a few hours.

Finally, ovulation predictor kits, available from drug stores, can detect the increase in luteinizing hormone (LH) in the urine just before ovulation.

Issues with the ovulation process can lead to infertility or difficulty conceiving.

Polycystic ovarian syndrome

A woman with polycystic ovarian syndrome (PCOS) has enlarged ovaries, often with small, fluid-filled cysts on them. It can lead to a hormone imbalance that can disrupt ovulation.

Other symptoms can include insulin resistance, obesity, abnormal hair growth, and acne.

PCOS is the of infertility in women.

Hypothalamic dysfunction

This happens when the production of the FSH and LH hormones is disrupted. These are the hormones that stimulate ovulation. This can affect the menstrual cycle.

Irregular menstrual cycles and amenorrhea, which means not menstruating at all, .

Causes of hypothalamic dysfunction excessive physical or emotional stress, extremely high or low body weight, or substantial weight gains or losses.

Excessive exercise, low body weight, and tumors of the hypothalamus can also lead to hypothalamic dysfunction.

Premature ovarian insufficiency

This is when egg production stops prematurely, due to a drop in estrogen levels.

It can be due to an autoimmune disease, genetic abnormalities, or environmental toxins.

It typically affects women before the age of 40 years.

Hyperprolactinemia, or excess prolactin

In certain situations, such as the use of medication or an abnormality in the pituitary gland, which produces hormones, women can produce excessive amounts of prolactin.

This, in turn, can cause a reduction in estrogen production.

Excess prolactin is a less common cause of ovulatory dysfunction.