Final answer:
For a woman with a BMI between 19.8 and 26, the recommended pregnancy weight gain is 25-35 lbs. This accounts for the proper growth of the fetus while managing health risks. An increase of only 300 extra calories per day during the second and third trimesters is typically sufficient.
Step-by-step explanation:
The recommended weight gain during pregnancy for a woman with a BMI between 19.8 and 26 is 25-35 lbs (Option B). This range is consistent with what is considered a healthy weight gain for someone of a normal weight before pregnancy. Factors contributing to weight gain include the growing fetus, enlarged uterus, amniotic fluid, placenta, additional breast tissue, increased blood volume, and some fat storage as a reserve for breastfeeding.
During the first trimester, the mother does not require additional calories, but in the second and third trimesters, just an extra 300 calories per day are advised to support the growing fetus. Excessive weight gain can lead to health risks such as gestational diabetes and obesity in the child later in life.