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Infertility

Last updated: May 1, 2025

Summarytoggle arrow icon

Infertility is the inability to achieve pregnancy after 12 months of regular unprotected sexual intercourse in female individuals < 35 years of age and after 6 months in those ≥ 35 years of age, or the need for medically assisted reproduction to achieve pregnancy. Causes of female infertility include diminished ovarian reserve, ovulatory dysfunction, and tubal, pelvic, uterine, and cervical disorders. Causes of male infertility include male hypogonadism and sperm transport disorders. Diagnosis involves assessing both partners to determine the underlying causes and typically includes hormone tests to assess ovulatory function, imaging to evaluate for uterine abnormalities and tubal patency, and semen analysis. Management includes treatment of the underlying cause and often medically assisted reproduction, including ovulation induction, intrauterine insemination, and assisted reproductive technology (e.g., in vitro fertilization).

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Definitionstoggle arrow icon

  • Infertility is characterized by: [1]
    • An inability to achieve pregnancy despite regular unprotected sexual intercourse; based on factors such as age and medical, sexual, and reproductive history
      • In female patients < 35 years of age: after 12 months
      • In female patients ≥ 35 years of age: after 6 months
    • The need for medically assisted reproduction to achieve pregnancy
  • Primary infertility: infertility in individuals who have never achieved pregnancy [2]
  • Secondary infertility: infertility in individuals who have previously achieved at least one pregnancy [2]
  • Diminished ovarian reserve: : a decline in the number of functioning oocytes (either as a normal consequence of age or due to an underlying disorder such as endometriosis) that manifests as a reduced response to ovarian stimulation in reproductive-aged women with regular menstruation [3][4][5]
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Epidemiologytoggle arrow icon

Infertility affects approximately 1 in 6 people in their lifetime. [6]

Epidemiological data refers to the US, unless otherwise specified.

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Etiologytoggle arrow icon

Female infertility

Male infertility

Sperm transport disorders

The cause of infertility remains unexplained in up to a third of affected couples. [7][8]

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Diagnosistoggle arrow icon

General principles [4][5][9]

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Female individualstoggle arrow icon

Initial assessment [2][4][5]

Approach

Ovulation tests

Options include:

Imaging

Further assessment [2][3][4]

Further assessment is typically performed by reproductive endocrinology and may include the following.

Although ovarian reserve testing can predict responsiveness to ovarian stimulation, it does not predict reproductive potential better than the patient's age and should not be performed to evaluate reproductive potential in female individuals without infertility. [3]

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Male individualstoggle arrow icon

Initial assessment [9][13][14][15]

Further assessment [9][13][14][15]

Further assessment is typically performed by urology and may include the following.

Antisperm antibodies form when the blood testis barrier is disrupted, usually due to infections or trauma of the male genital tract, and can lead to immobilization and agglutination of sperm or have a spermatoxic effect. [13][16]

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Managementtoggle arrow icon

Approach [2][5][9]

Ovulation induction [2][17]

The goal of ovulation induction is to stimulate development of a single dominant follicle in patients with anovulation. [17]

Ovulation induction increases the risk of multiple pregnancy, and ovulation induction with exogenous gonadotropins increases the risk of ovarian hyperstimulation syndrome. [17]

Other forms of medically assisted reproduction [5][22]

Assisted reproductive technology

In vitro fertilization may be combined with intracytoplasmic sperm injection and/or the use of donor gametes. [24]

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Complicationstoggle arrow icon

Patients who start assisted reproductive technology are at risk of complications related to ovarian stimulation.

Ovarian hyperstimulation syndrome (OHSS) [27][28]

We list the most important complications. The selection is not exhaustive.

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