Carrie Underwood believes her pregnancy is a ''true miracle''.

The 35-year-old singer is expecting her second child with husband Mike Fisher - with whom she already shares three-year-old son Isaiah - and after revealing over the weekend that she tragically suffered three miscarriages between 2017 and the start of 2018, she couldn't be more ''thankful'' to have a baby on the way.

A source said: ''Carrie is so healthy and happy. Carrie and Mike are so thankful for this precious time, they are great parents and have always wanted more children so they believe this is a true miracle.''

The 'Cry Pretty' hitmaker had a rough year in 2017, after having not only suffered two of her three miscarriages, but also having a scary fall which resulted in a broken rise and 40 stitches on her face.

But the source insists she has ''come a long way'' in recent months, and has been ''incredibly strong'' in the face of her hardships.

The insider added to 'Entertainment Tonight': ''2017 was one of the most challenging years of Carrie's life. She had big plans for herself and every step of the way she faced roadblocks.

''Carrie is a great mother and an amazing performer and wanted 2017 to be her year. She made some big changes in management but dealing with her career, her miscarriages, her fall and losing part of her team was almost more than she could handle.

''She has come a long way and we are all so proud of her. She is incredibly strong. She has an incredibly supportive family and leaned on them and her closest friends to get through it all.''

This weekend, Carrie revealed she had endured three miscarriages in the last two years, and said she was left feeling ''angry'' by the ordeal.

She said: ''I had always been afraid to be angry. Because we are so blessed. And my son, Isaiah, is the sweetest thing. And he's the best thing in the world. And I'm like, 'If we can never have any other kids, that's okay, because he's amazing.' And I have this amazing life. Like, really, what can I complain about? I can't. I have an incredible husband, incredible friends, an incredible job, an incredible kid. Can I be mad? No.

''[But after the miscarriages,] I got mad. [I thought], 'Why on Earth do I keep getting pregnant if I can't have a kid?' Like, what is this? Shut the door. Like, do something. Either shut the door or let me have a kid.''