1. Human Fertilisation and Embryology Authority. The responsible use of treatment add-ons in fertility services: a consensus statement. January 2019. www.hfea.gov.uk/media/2792/treatment-add-ons-consensus-statement-final.pdf.
2. Lack of evidence for interventions offered in UK fertility centres
3. Human Fertilisation and Embryology Authority. Treatment add-ons. www.hfea.gov.uk/treatments/explore-all-treatments/treatment-add-ons.