What Is the Main Cause of Infertility? Female & Male Infertility

Medically Reviewed on 2/9/2022
What Is the Main Cause of Infertility
Causes of infertility include age, ovulatory disorders, and abnormal sperm production or function. Learn about the main causes in both men and women

Infertility is the inability to get pregnant despite unprotected sex for at least a year. Common causes of infertility include age, ovulatory disorders, and abnormal sperm production or function.

Infertility is a common problem that affects approximately 15% of couples worldwide. While many factors contribute to reproductive disorders, some require targeted intervention.

Main causes of female infertility

Main causes of male infertility

  • Poor sperm quality
  • Low sperm count or lack of sperm
  • History of STI
  • Hormonal imbalances

Causes of infertility in both men and women

What factors lead to infertility in women?

For a woman, infertility can manifest as the inability to become pregnant, maintain a pregnancy, or carry a pregnancy to full term. Factors that can lead to female infertility include:

  • Fallopian tube damage: Damage to the fallopian tubes, which transport eggs from the ovaries to the uterus, can prevent the egg and sperm from making contact. Pelvic inflammatory disorders (PID) caused by different infections or pelvic surgery can cause fallopian tube damage. PIDs are most commonly caused by STIs.
  • Disrupted ovulation: During the menstrual cycle, synchronized hormonal changes occur, resulting in the release of an egg from the ovary (ovulation) and the thickening of the endometrium in preparation for the fertilized egg (embryo) to implant inside the uterus. Conditions that can cause ovulation difficulty include:
    • Polycystic ovary syndrome (PCOS): Interferes with normal ovulation
    • Functional hypothalamic amenorrhea: Absence of periods due to excessive physical or emotional stress
    • Diminished ovarian reserve or premature ovarian aging: Can cause trouble conceiving
    • Premature ovarian insufficiency: Occurs when ovaries stop functioning before age 40
    • Uterine causes: May include polyps and fibroids
    • Cervical causes: May prevent sperm from passing through the cervical canal


Men and women are equally likely to have fertility problems. See Answer

What factors lead to infertility in men?

In over 90% of cases, male infertility is caused by low sperm count, poor sperm quality, or both. Sperm abnormalities include:

  • Oligospermia (low sperm count, less than 15 million/mL)
  • Azoospermia (no sperm)
  • Asthenospermia (poor sperm motility)
  • Teratospermia (abnormal sperm structure)

Congenital birth defects, chemical exposure, and unhealthy lifestyle habits can also cause sperm abnormalities.

How is infertility diagnosed?

Evaluation of infertility includes medical history, clinical examination, and tests.

Preliminary investigations for an infertile couple are often focused on semen analysis, which should be done after 72 hours of sexual abstinence. Two analyses three months apart at the same lab are recommended.

Female infertility diagnosis may involve:

  • Detection of ovarian function
    • Hormonal assay: Checks for abnormal hormonal levels
    • Transvaginal ultrasonography: Detects ovulation and abnormalities in the uterus and adjoining structures
  • Evaluation of tubal patency
    • Hysterosalpingography (HSG): Dye is injected into the uterus while X-ray images are taken to monitor the movement of the dye into the fallopian tubes. Dye spilling into the abdominal cavity indicates that the tubes are patent.
  • Advanced investigations
    • Laparoscopy to visualize abdominal and pelvic organs (the uterus, fallopian tubes and ovaries)
    • Hysteroscopy for intrauterine lesions or adhesions
    • Chromosomal karyotyping for suspected genetic disorders

Male infertility diagnosis may involve:

  • Hormonal assay
  • Testicular biopsy
  • Chromosomal karyotyping for suspected genetic disorders

What are treatment options for infertility?

In most cases, infertility is treated with medications or surgery depending on the underlying cause. Treatment options include:

  • Ovulation medications
    • Help regulate the timing of ovulation
    • Promote the development and release of mature eggs
    • Aid in the correction of hormone imbalances that can affect the uterine lining
  • Intrauterine insemination
    • Involves using a catheter to inject sperm into the uterus
    • May be used in cases of low sperm count or problems with cervical mucus
    • Frequently used in conjunction with ovulation medications
  • Surgery
    • May treat conditions such as blocked fallopian tubes or endometriosis
    • Can correct anatomical issues that impede sperm production, maturation, or ejaculation
    • May be done to remove varicose veins in the scrotum (varicocele) which can occasionally improve sperm quality
  • Assisted reproductive technology (ART)
    • Involves fusing sperm and egg in a lab
    • Resulting embryo is then implanted in the uterus
  • Microsurgical fertilization
    • Intracytoplasmic sperm injection (ICSI), which involves injects a single sperm into an egg
    • The fertilization process is carried out under a microscope
  • Hormone therapy
    • Can help treat imbalances caused by hypothalamic, pituitary, or testicular problems that lead to sperm problems
    • May also include gonadotropin therapy, antibiotics, or other medications
Medically Reviewed on 2/9/2022
Image Source: iStock Images

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