13 weeks and you can pee!

The Babycenter update this week says that you're the size of a jumbo shrimp -- almost 3 inches -- and that you are starting to urinate the amniotic fluid that you've been swallowing. You better not be making a mess in there, bean!

Here's what's going on at 13 weeks, courtesy of Babycenter.com!

How your baby's growing: Your belly may soon be big enough to announce to the world that you're expecting, but your baby is still tiny. In fact, he's only about 3 inches long crown to rump — roughly the size of a jumbo shrimp — and weighs just about an ounce. Despite the small proportions, there's a fully formed baby inside your womb now. Much more proportional than it was a few weeks ago, his head is now only about a third the size of his body. If you could hold his hand, you'd notice the tiny, squiggly lines that make up his one-of-a-kind fingerprints. You'd also see his veins and vital organs beneath his tissue-thin skin. His kidneys and urinary tract are functional, and he's starting to urinate out the amniotic fluid he's been swallowing. As you start your second trimester, most of your baby's critical development will be completed, and your odds of miscarriage will drop considerably.