1. Metformin increases the pregnancy rate when added to the standard treatment of anovulatory polycystic ovary syndrome (PCOS).
2. Metformin in combination with clomiphene, is more effective than clomiphene alone or metformin alone improves fertility outcomes in women with PCOS of reasonably healthy body weight (BMI </= 32).
3. Metformin improves fertility outcomes in women with BMI > 32 with PCOS.

Inclusion Criteria:

• Women between the age of 18 and 39 years inclusive.
• Anovulatory infertility of duration at least 12 months.
• Polycystic ovary syndrome, based on Rotterdam consensus criteria.
• Normal serum prolactin, thyroid function and 17-hydroxyprogesterone.
• Normal serum prolactin, thyroid function and 17-hydroxyprogesterone;

Exclusion Criteria:

• Presence of any other significant infertility factor including male factor, known tubal disease or history of an ectopic pregnancy, known endometriosis affecting the fallopian tubes or ovaries.

• Already taking oral hypoglycaemics.

• Diabetics receiving treatment.

• Renal impairment

• Chronic hepatic disease

• Cardiac Disease

• Alcohol dependency

• Pre-disposition to lactic acidosis

• Previous ovarian drilling procedure, gonadotrophin injection therapy, IUI (intrauterine insemination) or IVF ( in vitro fertilisation).

• For those women who have had previous fertility treatment, the following would be excluded:

  • Women who have had > 5 cycles of clomiphene citrate
  • Women who have had > 5 months metformin treatment previously
  • Women who have proven to be resistant to 100mg or more of clomiphene citrate.