While in the European nation, Fergie reveals she saw horrifying scenes of poverty that left a lasting impact.
'She was one of many children I saw suffering: on that ward there were no proper drugs or anaesthetics, and one chemotherapy needle was being shared by them all,' she wrote.
'Anya taught me the meaning of courage and inspired the launch of my charity, Children in Crisis.'
Ferguson reveals her charity work has influenced her life in a way she could have never expected, including making her a 'better mother.'
She writes, 'It has certainly made me a better mother to my daughters Beatrice and Eugenie, giving me a sense of perspective, and allowing me to encourage them to use the platform they have to get involved in charitable work.'
'It has probably saved my life, too, by giving me purpose through hard times.
'As my grandmother always said, 'When you feel bad about yourself, go out there and do something for somebody else'.
'Again, lots of people told me that I shouldn’t do it, that it was bound to fail. But I was convinced that there was more that could be done.'
The 58-year-old recently revealed her charity Children In Crisis and Street Child had merged.
'Together they will strive to provide children with education and ensure that every child has the chance to go to school and learn. So happy to see charities coming together for a common goal!'