Anovulation, or lack of ovulation (the release of eggs from the ovary), is the primary cause of infertility in women. Without ovulation, your body releases no eggs for fertilization. Causes of anovulation include:

Abnormal Hormone Levels

This may indicate that your body isn’t being “signaled” correctly to begin ovulation. Specifically, a combination of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) is responsible for ovulation each month. If these hormones aren’t at optimal levels, which can sometimes happen as a result of physical or severe stress or significant weight loss or gain, ovulation may be irregular.

Polycystic Ovarian Syndrome

A hormone imbalance that results in the overproduction of male hormones, this is the most common cause of female infertility.

Primary Ovarian Insufficiency (POI)

Another cause for infertility in women, with POI, the ovaries cease functioning as normal ovaries would (releasing eggs), though the woman is not in menopause.

Luteal Phase Defect

This prevents the ovary from releasing enough progesterone, a hormone that helps the uterine lining prepare for a fertilized egg.

Interruptions in the Pathways of the Reproductive System

Other infertility factors include the inability of the fallopian tubes to carry eggs from the ovary once they are released to the uterus. This is usually caused by scar tissue created as a result of a condition called endometriosis or infection that results in pelvic inflammatory disease.

Damaged Fallopian Tubes

Damaged fallopian tubes may keep sperm from getting to the egg, or prevent a fertilized egg from making its way into the uterus. Reasons for damaged or blocked fallopian tube include:

  • previous surgery
  • prior ectopic pregnancy (a pregnancy in which a fertilized egg implants and begins growing in the fallopian tube instead of the uterus)
  • inflammation or scarring of the fallopian tubes due to a sexually transmitted infection

Unfavorable conditions in the uterus may also prevent fertilized eggs from implanting. These include:

  • fibroid growths
  • endometriosis
  • tumors
  • irregular uterine shape
  • cervical deformities
  • previous dilation and curettage (D&C)