The following three causes of infertility comprise over 80% of all major infertility issues. During infertility workup, over 80% of infertile couples have one or more of these problems:

  1. Ovulation Problems (often related to the mother's age):  Anovulation and low egg quality
  2. Male Factors (sperm problems): Low sperm count and low quality sperm 
  3. Pelvic factors (for example, problems with the fallopian tubes) Fallopian tube problems

 Below are facts concerning the percentage distribution of fertility problems:

  • About 25% of cases of infertility are due to ovulation problems such as anovulation and polycystic ovary syndrome (PCOS);
  • 30% are caused by pelvic factors such as endometriosis, adhesions, or tubal disease, and
  • 35% are due to male factors such as an abnormal sperm count (for example, oligospermia or not enough sperm, increased semen viscosity, decreased sperm motility, or decreased semen volume).
  • Less than 5% of infertility is caused by abnormal cervical mucus penetration, antisperm antibodies, or corpus luteum defects (CLP).
  • In about 10-15% of couples, no specific reason for infertility can be found on initial evaluation. This is called (unexplained infertility). But on further evaluation and treatment, occasionally factors such as poor sperm penetration or abnormal-appearing oocytes (eggs) are discovered.