A UK mom bravely chose to have her leg amputated to save her unborn baby when she was diagnosed with cancer, The Mirror reported.

Kathleen Osborne, 28, had no idea she was pregnant when she went for an MRI scan diagnosing cancer for the third time.

When doctors found that she was also pregnant, Kathleen had to make a choice between aborting her baby so she could start chemotherapy, or have her leg amputated.

Kathleen took one night to make her life-changing decision and she had her entire right leg amputated at four months pregnant, eradicating the cancer.

But sadly, she still had to give birth to daughter Aida-May eight weeks early after an MRI scan revealed cancer on her lungs had returned—and this time it was inoperable and terminal.

Kathleen was first diagnosed with cancer when she was just 11, after a painful lump on her right leg turned out to be osteosarcoma in 2005.

She had chemotherapy for the bone cancer and had most of her kneecap removed as well as two metal rods inserted into her leg.

Kathleen was clear of cancer for 11 years and welcomed two sons, Hayden, now nine, and Leo, now five, before she discovered that the cancer had returned in 2016, this time on her lungs.

Thankfully, the chemotherapy managed to shrink the cancer on Kathleen's lung considerably, and doctors only had to remove the lower lobe of her lung.

She was given the all clear in March 2017. But just three and a half years later, another painful lump on the top of her right leg appeared that left her almost unable to walk.

An MRI scan revealed it was cancer again but also showed a mysterious mass in her pelvis area, leading doctors to give Kathleen a pregnancy test that turned out to be positive.

"The doctors gave me two choices. They said I could either terminate my baby, have chemotherapy, have an operation and most likely lose my leg, or keep my baby and have my leg amputated straight away.

"They gave me a week to make the decision and told me the sooner I had the surgery, the better."

Ten days after making the difficult decision, Kathleen underwent surgery on November 17 to have her entire right leg amputated from her pelvis downwards.

She spent the first eight days after her amputation unable to look down at her remaining leg as she struggled to comprehend what had happened.

The amputation eradicated the cancer and Kathleen spent the rest of her pregnancy adjusting to life with one leg, using crutches the entire time after refusing a wheelchair.

Following her terminal diagnosis Kathleen is now doing all she can to make memories with her three kids whilst undergoing chemotherapy to give her more time with them.

The mom-of-three said she has no regrets over her decision to amputate her leg as it meant Aida-May was born.