Charlotte Church has sparked rumors she is pregnant after she abstained from alcohol at her 21st birthday party.The singer stayed sober as she celebrated the landmark occasion with close family and friends on Wednesday, fuelling speculation she is expecting. Charlotte is said to have cancelled a big bash at Cardiff's Hilton hotel, choosing instead to have the intimate gathering at her home. She has also given up smoking and friends claim she has put on weight, despite being on a diet. Charlotte recently revealed she would love to have children with her rugby ace boyfriend, Gavin Henson, and would agree to marry him if he asked. She said: "We're so happy - I'd like to have his kids. I love him and he's the one."However, she also added it might be a little early for her and Gavin, 25, to start a family. She said: "We're both really young. I've got a great career and he's got a great career. I think my grandmother would say, 'Wait a bit'."Charlotte is about to host the second series of her TV chat show, 'The Charlotte Church Show'.