Mia's Pregnant Belly

So apparently in the next episode, Mia goes into labor. I only know this from the guide info on my cable. But this surprises me because she never really looked all that pregnant. Her belly did not look big enough to be about to give birth. Now I know not all women get very big when pregnant--I just feel like they would have given her a more noticeable belly before they had her go into labor, if for no other reason than to make her pregnancy noticeable since it's a tv show.