Third-line treatments are considered when first-line and second-line options have not been effective, and this chapter covers three of them. Inositol, a supplement that acts as an insulin sensitiser and may improve metabolic measures, is discussed with a clear note on where its benefits for ovulation, hair growth and weight remain uncertain. Laparoscopic ovarian drilling is explained as a minor surgical procedure under general anaesthesia for women whose fertility has not improved with medication. The chapter then outlines IVF, from collecting eggs to fertilising them in a laboratory, as a possible next step when medication has not led to pregnancy.