Week 6: What's happening this week

Our baby's heart is growing, and dividing into the right and left chambers. But the most exciting part is that her tiny heart is now beating (at a speedy 100 to 130 beats a minute) and pumping blood throughout her body. The cells that will make up all of our baby's body parts and systems are dividing furiously as her body begins to take shape. Right now she's about the size of a small lentil bean (4 to 5 millimeters across). She's starting to build muscle fibers, and halfway through this week, she'll likely start moving her tiny limbs.