From months one through four, your baby will continue growing at the same rate he established during his first few weeks of life. In general, babies gain between 1 1⁄2 and 2 pounds (0.7 to 0.9 kg) and grow 1 to 1 1⁄2 inches (2.5 to 4 cm). Their head size will increase in circumference by about 1⁄2 inch (1.25 cm) each month. These figures are only averages, however, so keep track of your child’s development.
At two months, the soft spots on your baby’s head should still be open and flat, but by two to three months, the soft spot at the back should be closed. Also, his head is more likely to be proportionately larger as compared to his body because it is growing faster. This is quite normal; his body will soon catch up.
At two months, your baby will look round and chubby, but as he starts using his arms and legs more actively, muscles will develop. His bones also will grow rapidly, and as his arms and legs loosen up, his body and limbs will seem to stretch out, making him appear taller and leaner.