Causes of Subfertility and Infertility – Female Factors

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Female Infertility Factors

Click on sections below to reveal various factors.

Diminished ovarian reserve

  • Oocyte quantity and quality
  • A decrease in the quantity or quality of oocytes can affect women of reproductive age with regular menses and a reduced ability for multiple births compared with women at a comparable age.9, 11, 19, 24 Factors that are associated with diminished ovarian reserve include:
    • A smaller initial pool of follicles or abnormally rapid degeneration
    • Exposure to systemic chemotherapy, pelvic irradiation, and genetic abnormalities
    • In most cases, factors are unknown


Conception rate:

  • The conception rate for a 25-year-old woman is 60% in six months and 85% in twelve months. This rate is halved at age 35 years.25
  • All oocytes are produced during fetal development. The finite number of oocytes implies that fertility decreases with advancing age, the risk of congenital abnormalities increases due to aging oocytes, and the live birth rate decreases.26
  • Premature menopause (premature ovarian insufficiency) is the cessation of ovarian function and menstruation before the age of 40.27

Ovulatory dysfunction

Definition and cause:

  • Ovulatory dysfunction is defined as a history of oligomenorrhea or amenorrhea, or as luteal progesterone levels repeatedly less than three ng/mL, or both.
  • Although ovulatory dysfunction frequently results in oligomenorrhea or amenorrhea, it can have more subtle effects.
  • Common causes of ovulatory dysfunction include:14
    • Hormonal: PCOS, hypothalamic and pituitary dysfunction, hypo-, and hyperthyroidism, hyperprolactinemia
    • Medical: Obesity, eating disorders and underweight, tumors

Tubal factor

Blockage or damage:

  • Tubal factor infertility is due to fallopian tube blockage or damage preventing fertilization or egg transport.13 Tubal factor infertility is frequently caused by:
    • Sexually transmitted diseases which can cause pelvic inflammatory disease and salpingitis.
    • Endometriosis
    • Ectopic pregnancy
    • Uterine infection due to abortion or miscarriage
    • Adhesions and blockage
    • Infection: Infections are a common cause of tubal factor infertility. Tubal factor, including tubal occlusion, is responsible for more than 40% of infertility cases in Sudan, and 80% of cases in Central Africa.28, 29

Uterine and cervical factors

Implantation problems:

  • Uterine abnormalities may interfere with implantation of the fertilized egg and fetal development, include:30
    • Congenital uterine anomalies such as bicornuate or septate uterus
    • Endometrial polyps
    • Fibroids
    • Endometriosis
    • Cervical polyps


Impact on fertility:

  • Smoking, alcohol or illicit drug use, obesity (BMI, ≥30 kg/m 2 ), very low body weight (BMI ≤19 kg/m 2 ), and excessive physical activity can be associated with a lower fertility rate.16, 31-33

Unexplained Infertility

No visible abnormality:

  • Unexplained infertility accounts for up to 30% of all infertility. In this setting, evaluation tests do not show any abnormality, but infertility criteria are met. These tests include:12
    • demonstration of at least one patent fallopian tube
    • documentation of ovulation, and
    • semen analysis showing adequate number and motility of sperms

Note: References are listed at the end of the course.

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