Carrie Underwood thinks she's ''missed her chance'' to have a big family.

The 35-year-old singer has three-year-old son Isiah with her husband Mike Fisher, and although she wouldn't mind having more children, she is worried she may have missed the boat in terms of her age when it comes to having a larger brood.

When asked if she wants a big family, she said: ''I'm 35, so we may have missed our chance to have a big family.''

But the 'Cry Pretty' hitmaker hasn't completely given up on the idea of having more children, as she admits she's looked into some other options.

She added to Redbook magazine: ''We always talk about adoption and about doing it when our child or children are a little older. In the meantime, we're lucky to be a part of organisations that help kids, because our focus right now in our lives is helping as many kids as possible.''

Carrie's comments on motherhood come after she revealed in 2016 that she sometimes finds it difficult to juggle her hectic schedule when ''professionalism and mommyhood collide''.

Speaking about her plans for Halloween, Carrie said: ''I'm not going to lie, it's difficult when professionalism and your mommyhood collide - which is on a daily basis - but it's wonderful.

''It's like bring your baby to work every day. He's just there, and it's great he's on the bus and helping me get ready. It might make things take a little longer, but he's just my little sunshine. He makes me happy all day.

''[But] I've blocked off some time to be able to take him trick-or-treating a little bit and got him a costume and everything.''

The 'Before He Cheats' singer also admitted she feels ''guilty'' her son's life has to revolve around her job, which sees them spend hours on a tour bus and stay in a variety of hotel rooms ''in the middle of nowhere'' when she is on tour.

She explained: ''Sometimes I feel guilty that this is my son's life: We live on a bus and we're in a hotel room and sometimes we're in the middle of nowhere and it's not so great. It's not all glamorous.''