Premature ovarian insufficiency (POI) is a heterogeneous diagnosis caused by a multitude of factors including genetic, autoimmune, iatrogenic, social, and environmental. It is defined as loss of ovarian function prior to 40 years of age with subsequent secondary amenorrhea for at least 4−6 months in conjunction with elevated follicle stimulating hormone levels on two different measurements. Prompt recognition of symptoms should encourage thorough history-taking and work-up, as some causes of POI are associated with conditions requiring additional screening or medical management. Early initiation of hormone replacement therapy is necessary to prevent long-term sequelae from chronic hypoestrogenism such as cardiovascular events, poor bone health, and cognitive dysfunction. Extensive counseling with regards to future fertility and family building options is necessary as the diagnosis of POI can be psychologically devastating to many women.

As women age, their response to ovulation induction is progressively diminished due to the continuous depletion of primordial follicles and to changes in the ovarian endocrine/paracrine microenvironment. While many couples faced with the reality of a diagnosis of low functional ovarian reserve may turn to the use of donor gametes to achieve a pregnancy, some still feel the need to try on their own, despite a poor prognosis. For such women careful preparation and hormonal priming in the months prior to beginning an IVF cycle can increase their chance of a successful outcome. Optimal treatment of these patients differs from the usual treatment of women with normal ovarian reserve in every aspect and needs to be highly individualized.

Anovulation represents one of the main causes of female infertility, and establishing the underlying cause is critical to ensure effective treatment. This chapter details the various disorders of ovulation, including polycystic ovary syndrome, which is the most common cause. It discusses the systematic approaches to treating disorders of ovulation and reproductive endocrine disorders associated with infertility.