NHS England and the Department of Health and Social Care (DHSC) have been alerted to a supply disruption of Hologic fetal fibronectin (FFN) cassettes. The disruption is due to a quality control issue with the raw material used to make the cassettes and this is temporarily disrupting their manufacture and supply. Hologic estimates recovery for this product to be May 2023. This letter  recommends a number of adjustments to clinical practice.