C.C. - The Nanny
The Nanny decided to have a bit of fun with Lauren Lane's pregnancy, using blatantly obvious props to hide it, such as this giant Broadway poster. They also wrote in a plot device in which she gains weight, loses her sanity, and even has to be institutionalized!
Lily - How I Met Your Mother
We learned that Lily was a hot dog eating champ, once eating 29 hot dogs in 8 minutes, earning her the nickname "the belly." Of course, after winning, she just had to show off her super stuffed stomach not just once, but twice! She later broke her own record at MacLaren's.
Grace - The Mentalist
Grace basically spent the season stuck behind a desk or hiding behind random objects like boxes, purses, and even a water cooler. It was almost like a game to see what new thing she would be sitting or standing behind next!
Lemon - Hart of Dixie
Unlike Rachel Bilson, who's pregnancy was written into the show, Jaime King's Lemon Breeland had to hide behind tables, flowers, purses, and bottles of ketchup and mustard, all before being shipped out of Bluebell to care for an ailing grandmother.
Angela - The Office
When your setting is an office, it makes hiding a pregnancy a little easier. Angela hid behind her desk, the copier, doorways, and whatever else they could find. But, not every scene was in the office, so that's where things like throw pillows came in.
Jenna - 30 Rock
In season 5, Tracy Morgan was written out for most of it because of his kidney transplant, so when Jane Krakowski got pregnant, they couldn't afford to write her out too. While most of the season they employed the standard scarf, purse, folder cover-ups, the dog costume used in the season finale was by far the best belly bump disguise.