Your baby now is about the size of a medium green olive. The crow-to-rump length is 22 to 30 mm and the baby weighs 0.12 ounces. Although the baby is still very small, it is beginning to look more like a human being. Your baby's back is straightening out and the tail is shrinking. In proportion to the rest of his body, the head is large and remains curved forwards onto the chest. The head is erect and the neck is developing well. Even though your baby's eyes are well developed, they are covered by a membrane lid. The eyes will not begin to open and close for quite some time still. Your baby will begin to make tiny movements as the muscles start to develop. You will not be able to feel any of these early movements, but you might be able to see them during an ultrasound. The arms and hands are progressing faster than the legs and feet at this point. By this time of your baby's development, the hands have defined finger ridges and the tissue between them will die off to leave separate fingers. It is impossible to distinguish a male from a female at this time because external genitalia look very similar at this point. Your blood system will change during pregnancy and blood volume will increase by 50%. The increase in blood is important to meet the demands of your growing uterus. Blood volumes will begin to increase during the first trimester and will continue to rise throughout the entire pregnancy. The increase in plasma can cause anemia, which will cause you to feel tired or weak.