Originally Posted by alwatson:
“Why? Why do you doubt she is pregnant? Why do people always doubt things like this? Why WOULDN'T she be. Why would she lie/be wrong.”
It's got nothing to do with whether or not Amy is the sort of person who would lie, or that pregnancy is the sort of thing someone would make up. It has a lot to do with the Doctor's adventures not being the sort of thing that a pregnant woman would fit into.
It's entirely plausible from the perspective of the characters that she be pregnant, but seems unlikely for us at home, who know that the rest of the series will involve running around and dangerous stunts and life-threatening aliens - not the sort of environment that even the BBC would put a supposedly pregnant character into without attracting a lot of criticism. They did that once in Amy's Choice, and made much of how restrictive it was for her.
Of course, perhaps she is pregnant, but then forgets about it...