Discover the amazing changes that happen each week as your baby grows and develops, from a tiny cluster of cells all the way to becoming a squalling newborn.
From a few gathered cells, an embryo has grown in seven weeks to a collection of developing blood vessels, vertebrae and internal organs (including a kidney that produces urine). The embryo is now half an inch long. The fingers are webbed and spread like starfish. Toes begin to sprout and feet take shape. Facial features organize as the retinas form, eyelids begin to develop, and the palate and ear canals begin to take shape. In males, the penis begins to form. In girls, the clitoris and the ovaries appear.
The embryo now measures 16 millimeters, about the size of a postage stamp. It looks more like a fetus, curled in the familiar fetal position and its legs are extended and arms have defined, bent elbows. The developing eyelids begin to close up, the external ears have begun to form, the nostrils are defined and open and the upper lip has begun to form.
The embryo measures 1.25 inches from crown to rump and weighs 1/30 of an ounce. Taste buds develop, the toes separate, and the intestines move out of the umbilical cord and fully into the embryo's body. All the organs are in place and distinctly formed. Now they must grow in size and become interconnected. As they do, the embryo becomes a fetus.