Week 10

The babies are now barely the size of a kumquat, and weigh less than a quarter of an ounce. (Length: a little over 1 inch, head to bottom.)

They are swallowing fluid and kicking up a storm. Vital organs — including kidneys, intestines, brain, and liver (now making red blood cells in place of the disappearing yolk sac) — are in place and starting to function, though they'll continue to develop throughout pregnancy. They can even begin to hear sound this week as the inner workings of the ear are complete!

If you could take a peek inside my womb, you'd spot minute details, like tiny nails forming on fingers and toes (no more webbing) and peach-fuzz hair beginning to grow on tender skin.

In other developments: The baby's limbs can bend now. Hands are flexed at the wrist and meet over his heart, and feet may be long enough to meet in front of the body. The outline of the spine is clearly visible through translucent skin, and spinal nerves are beginning to stretch out from the spinal cord. The baby's forehead temporarily bulges with his developing brain and sits very high on his head, which measures half the length of his body. From crown to rump, they are about 1 1/4 inches long. In the coming weeks, the babies will again double in size — to nearly 3 inches!