Nature has an incredibly useful way of letting expectant women know that their pregnancy is coming into the home stretch. As if the bulging belly and inability to go 30 seconds without resting, peeing or eating weren't evidence enough, many women will start to get an extra cue from their belly button.

Much like a pop-up turkey timer lets you know when your bird is done, a pregnant woman's belly button lets you know when your bun is almost ready to come out of the oven, too. As the belly expands more in late pregnancy it presses on the tissue in your belly button and often causes an "innie" to become an "outie". While this doesn't happen for everyone, it is a relatively common occurrence, often starting around the sixth month.

I like to push on my wife's pregnant belly button; it's a little squishy, yet resilient. It reminds me of a little priming pump you find on the side of a gas-powered weed whacker. While hers is not yet a complete outie, it will probably get pretty close at some point in the next three months.

A little fashion tip for pregnant mommies who don't want their turkey timer belly buttons poking through their shirts, use a band-aid or a little bit of tape to keep that bad boy in check.