Final answer:
An underweight pregnant woman with a BMI of 17.5 is recommended to gain more weight during pregnancy, about 28 to 40 pounds, which is more than the standard for those with a normal BMI. The weight gain should include approximately 1 pound per month in the first trimester and about 1 pound per week during the second and third trimesters, aided by an increase of approximately 300 calories per day.
Step-by-step explanation:
The discussion about weight gain during pregnancy involves understanding the body mass index (BMI) and appropriate weight gain based on that index. A BMI of 17.5 falls in the underweight category, as a normal BMI ranges between 18 and 24.9. For an underweight pregnant woman, it's recommended to gain more weight compared to those with a normal BMI, primarily during the second and third trimesters when the appetite increases and additional calories are necessary to support the growing fetus.
Guidelines generally suggest that women with a low BMI at the start of pregnancy should aim to gain more - around 28 to 40 pounds throughout pregnancy - which is higher than the standard recommendation of 25 to 35 pounds for women with a normal BMI. This is because the additional weight supports the health of both the mother and the fetus, including ensuring there are adequate resources for the increased metabolic demands of breastfeeding postpartum.
Weight gain should be gradual, with approximately 1 pound per month during the first trimester, and around 1 pound per week during the second and third trimesters, with an increase of around 300 calories per day. However, a healthcare provider should provide personalized recommendations based on individual health and pregnancy progression.