Final answer:
A normal weight gain in pregnancy is approximately 25 to 35 pounds, closest to option B. 20 pounds. This includes the weight of the fetus, increased blood volume, and minimal fat storage.
Step-by-step explanation:
A normal weight gain in pregnancy for women is said to be roughly 25 to 35 pounds for those who are of a normal weight before becoming pregnant. This translates to an answer closest to B. 20 pounds. However, it should be noted that this number can fluctuate depending on the individual's pre-pregnancy weight, metabolism, and medical conditions. Weight gain in pregnancy is spread out across the different components such as the growing fetus, enlarged uterus, amniotic fluid, additional breast tissue, and increased blood volume. Only about 2.3 kg (5 lbs) of the weight gain in a normal pregnancy is actually due to fat storage.
During the first trimester, a pregnant person typically gains about 1 pound per month without requiring additional calories. It is in the second and third trimesters that an additional intake of about 300 calories per day is recommended to support the growing fetus, leading to a weight gain of roughly 1 pound per week during these stages.