What is going on with Katie's baby bump?

Trent at Pink is the New Blog has always been suspicious of the varying size of Katie Holmes' baby bump. He has a point. In the very fist picture we saw of Katie after she and Tom Cruise announced she was pregnant, she was HUGE! Since then, depending on what she was wearing, her size seems to fluctuate quite a bit. It could all be a matter of how slimming her clothes are, but it is a little shady sometimes. Here is a timeline of her pregnancy development. Why is this whole thing so sketchy?

{Click on image to see larger}

{Image Source}