Causes of infertility can be broadly divided to male factor only (35%), female factor only (35%) or combined (20%). In 10% of couples, no causes can be identified (unexplained).
Female factors
- lack of ovulation (egg production) due to advanced age, excessive weight loss or polycystic ovaries
- endometriosis i.e. abnormal old menstrual blood in the areas behind the womb or within the ovaries
- blocked fallopian tubes due to infections
- distortion of the womb due to congenital abnormalities or fibroids
Male factors
- No sperm production due to failure of the testicles or obstruction of the connecting ducts
- Poor sperm quality due to varicocele (dilated veins in the testis leading to overheating), inherited causes, smoking
- Sexual difficulties e.g. erectile dysfunction or in ability to ejaculate