Did anything in the above photo catch your eye? If you're a guy, you didn't see anything strange. If you're a gal, you noticed something. Angela Kinsey, who plays uptight accountant Angela Martin, is wearing a light blouse and a dark jumper. And wait! Her arms don't look right. Why would her arms be folded that way? It doesn't look natural... She must be pregnant. And she was for most of Season 4, but her pregnancy did not fit in with her character's life, so they used little tricks to hide it. On many occasions, she would hide behind her desk, the copier, a bouquet of flowers, another actor, or a door.
Sometimes they just shot her from the chest up.
If you're a guy and still don't believe me, take a look at the following photo. It shows Angela (and Rainn Wilson) at her onset baby shower. There's no getting around the fact that she is expecting.
While watching the later episodes of Season 4, my mom and I immediately picked up on Angela's pregnancy and would mention something about it, with my dad being oblivious: "What? She's pregnant?" Upon talking to other fellow Office fans, it seems the trend is strong: Gals were aware of Angela's pregnancy, while guys were clueless.