Where does the weight go?

Here's an approximate breakdown of weight gain:

Baby: 7-8 pounds
Placenta: 1-2 pounds
Amniotic fluid: 2 pounds
Uterus: 2 pounds
Maternal breast tissue: 2 pounds
Maternal blood: 4 pounds
Fluids in maternal tissue: 4 pounds
Maternal fat and nutrient stores: 7 pounds
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TOTAL: Weight gain depends on a number of factors including height, body type, and pre-pregnancy weight. However, most women who are carrying twins are encouraged to gain 35 to 45 pounds.