Ovulation induction is the action of bringing about ovulation through oral or injectable hormonal medication. This process is used in female patients who have irregular (oligo-ovulation) or absent (anovulation) menstrual cycles. Causes vary and include dysfunction of the hypothalamic-pituitary-ovarian axis, anomalies in thyroid hormone or prolactin secretion, and hyperandrogenism, most commonly as a result of polycystic ovarian syndrome. Ovulation induction is usually achieved by the administration of oral or injectable medications and can be monitored at home through basal body temperature curves and cervical mucous observation, or in the clinic by the use of hormonal blood tests and pelvic ultrasounds. Ovulation induction can be coupled with intrauterine insemination (IUI) in case of the presence of male factor infertility.