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.