Meet Sienna, first baby to be born after pioneering ovarian surgery to a mother with breast cancer 

A baby who is the first to be born after pioneering fertility treatment is giving hope to patients that they can have children of their own after suffering cancer.

Sienna Pear was born in April, four years after her mother Shana, then 33, was diagnosed with aggressive breast cancer.

Ordinarily, her treatment would have left her infertile. But under the breakthrough procedure, doctors removed one of her ovaries a week before she began her battle to beat the disease.

Strips of tissue containing eggs were frozen at a temperature of minus 180C, effectively putting them into hibernation.

A baby who is the first to be born after pioneering fertility treatment is giving hope to patients that they can have children of their own after suffering cancer

When Mrs Pear finished her cancer treatment, the tissue was re-implanted. Healthy eggs were harvested and one fertilised with husband Charles's sperm via IVF.

Mrs Pear was not allowed to conceive naturally to minimise her time off Tamoxifen, a hormone therapy for breast cancer.

The couple wept when they heard Sienna's heartbeat in the womb and were overjoyed when she became the first baby to be born following the new treatment.

'It was so emotional and we just felt so blessed,' said Mrs Pear, a social worker, of Barnes, south-west London. 'Our daughter is the light of our lives.' Her husband added: 'She is a miracle.'

Shana was diagnosed with aggressive breast cancer aged 33. Pictured here with her husband Charles

Doctors behind the NHS programme – the National Paediatric Fertility Preservation Service – say their work could help tens of thousands of cancer survivors.

Notably, it can benefit children and young adults with around 2,700 having had reproductive tissue removed and frozen in the nine years the service has been operating.

They include a girl aged just four months with acute myeloid leukaemia. The process is different to conventional IVF as tissue is removed immediately.

The service has no central funds and relies on the goodwill of staff but NHS England is considering proposals to pay for it nationally.