Child Development - Learn how a fetus grows throughout the nine months of pregnancy. Embryo, fetus, development, pregnancy. Tiny limb buds, which will grow into arms and legs, appear.
Embryo looks like a tadpole.
Heart and lungs beginning to form. By the 25th day, heart starts to beat. Neural tube, which becomes the brain and spinal cord, begins to form. You become pregnant and miss your period. Your breasts are slightly bigger and sore.