The amount of weight your spouse needs to gain during pregnancy depends upon how much she weighed before she became pregnant.
According to the American College of Obstetricians and Gynecologists (ACOG) women who have a normal weight before getting pregnant should gain 25 to 35 pounds. Women who are underweight before pregnancy are advised gain 28 to 40 pounds. And it is recommended for women who are overweight to gain 15 to 25 pounds. Research now shows that women who gain more than the recommended amount during pregnancy have a higher chance of being obese 10 years later.
You should ask your doctor how much weight gain during pregnancy is healthy for your spouse.