The five-month embryo is about eight inches long and weighs about half a pound. The lungs and digestive organs are not yet fully developed. The mother can now feel the baby as it turns and kicks. At seven months the fetus is about twelve inches long and weighs two to three pounds. Calcium and iron from the mother are being used in the final formation of the skeleton and the blood. At nine months the fetus, now capable of an independent existence, moves into a vertical head-down position facing the mother's back. At birth the baby usually weighs between six and eight pounds.