**Core Concept**
The Institute of Medicine (IOM) guidelines recommend weight gain during pregnancy based on the woman's prepregnancy body mass index (BMI). For women with a BMI of 30 kg/m^2, which categorizes them as obese, the recommended weight gain is lower to minimize the risk of complications.

**Why the Correct Answer is Right**
Women with a prepregnancy BMI of 30 kg/m^2 are at an increased risk of gestational diabetes, hypertension, and other pregnancy complications. The IOM recommends that these women gain 11-20 pounds (5-9 kg) during pregnancy, which is lower than the recommended weight gain for women with a normal or underweight BMI. This reduced weight gain helps to minimize the risk of complications and improve pregnancy outcomes.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct weight gain for obese women. The recommended weight gain for women with a BMI of 30 kg/m^2 is lower than for women with a normal or underweight BMI.

**Option B:** This option is incorrect because it is too high for women with a BMI of 30 kg/m^2. Women with a higher BMI are at an increased risk of complications and should gain less weight during pregnancy.

**Option C:** This option is incorrect because it is too low for women with a BMI of 30 kg/m^2. While women with a higher BMI should gain less weight during pregnancy, they still need to gain enough weight to support fetal growth and development.

**Clinical Pearl / High-Yield Fact**
It's essential to assess a woman's prepregnancy BMI and provide individualized recommendations for weight gain during pregnancy. This can help minimize the risk of complications and improve pregnancy outcomes.

**Correct Answer:** C. 11-20 pounds (5-9 kg)