Building a baby requires a lot of extra poundage. If you started your pregnancy at a healthy weight, by the time you give birth you should have packed on between 25 and 35 pounds -- and probably only 7 to 8 pounds of that will be the baby itself. What accounts for the extra pregnancy weight gain? Everything from amniotic fluid (2 pounds) to an increased blood supply (4 pounds). Keeping your pregnancy weight gain in check can be a challenge. (Have you gained too much? Not enough?) Use our pregnancy weight gain chart to find out if your weight gain is on target for your pregnancy.