Would Lydia Be Showing ? - Possible Spoiler!!

She was only two months pregnant so she would not be showing yet. however when they showed the fetus that Tuck saw it was more developed than a two month fetus should have been. Also tuck would not have been able to get that close. I dont think that they gave a time gap to the wedding so if it was withing a month than she wouldnt be showing or have a baby at the wedding.

Maybe she was only two months pregnant at the time, because she leaves him at the beginning and then it says Two Months Later. And the wedding at the end might have been shortly after the adventure because they are reunited. Actually, at the end, since the villians are still half-size, maybe not a lot of time had passed since I think the villians by then would've found a way to return to normal size. Just a thought as I'm typing.

Actually, in my opinion, the movie is very accurate for Lydia's pregnancy.

The storyline strongly hints that the reason WHY Lydia leaves Tuck at the start at the movie is because she already knows she's pregnant - comments such as "things are different now", she isn't shown to be drinking alcohol at any stage of the movie - including at the beginning when everyone else is. Obviously feeling torn because of their situation (he's just resigned his commission, keeps getting drunk etc) she panics over the thought of him being an unfit/unsuitable father.

So, with this in mind, she'd already have to be at least a month pregnant to know about it - fast forward to 2 months later, which would make her approx. 3 months :) The fetus looks correctly developed for around that stage (google is your friend!), and most women don't start showing until around 4-5 months for their first pregnancy.

We can only assume it was a shotgun wedding, which, given the circumstances at the end of the flick, wouldn't be unusual.

So there ya go :)

Fortunately it's a silly comedy/science fiction move, not a documentary about human pregnancy, so it really doesn't matter.