Whilst undergoing fertility treatment, you will not be entitled to statutory time off.  However, the Advisory, Conciliation and Arbitration Service (ACAS) guidance states that employers should treat appointments related to IVF in the same way as any other medical appointment, under the terms and conditions of the contract of employment. If the implantation is successful, you will be entitled to maternity leave. You should consult your employment contract to find out on what terms.