@AHK and a few other posts
I think the panel was meant to deceive. The problem isn't the manga, however, it's Kishimoto. He has no problem destroying what he's built up or retconning what was never there to begin with. So the whole prospect of looking for foreshadowing or trying to establish a pattern is pointless. Kishimoto can turn it over in the end.
I tend to think the panels are meant to show Sakura as being there, but hide definitively whether she was pregnant or not. My theory is that she's pregnant...for the simple reason that I don't think Kishimoto is brave enough to make Karin the mom. (After all, there is a female who got treated worse than Sakura did in the manga - and that's Karin. He's not going to make her a heroine-type now.)
But even if he did show Sakura as full blown pregnant, he could always turn it around in the end and say it was Karins child, and that is was just a windy day, she had on a billowing dress and that we, the audience, were reading it wrong.
Remember in the manga, Naruto said Sakura was his girlfriend and Minato gave his tacit blessing. But he still flipped the story and blamed the readers, passing the whole thing off as a red herring.
That dude can and will do whatever he wants. We may all have opinions, but Kishimoto doesn't care about his audience, his characters or his story. So it makes it really hard to look at the story with a critical eye now. He'll change it to suit whatever he wants.
And it sucks that in a story about shinobis he's boiled it down to a "Who's My Mummy?" between the two characters he treated the most poorly in the original work.
If you had asked me to come up with a storyline for Part 3, in my wildest dreams I could never have picked the one we got.
This is where we use the assassin's creed motto.
"Nothing is true, everything is permitted."
