Something very interesting is happening in this, the start of your second trimester: your little fetus is starting to display his own unique personality. From this point on, different fetuses show different facial expressions. Some research even indicates that certain fetuses may start to smile at 15 weeks. Your baby may have started sucking his thumb! The brain has developed structurally; from this point on its mass will increase greatly.

Your little one is looking more and more human. The eyes continue to move forward, and the ears are moving up to their final position. The neck is straighter and stronger, so he can now turn his head. The fetus is beginning to move around more in his amniotic swimming pool, although you can't yet feel those movements.