Final answer:
Underweight women with a prepregnancy BMI below 18.5 should aim to gain between 28 to 40 pounds during pregnancy. Excessive weight gain can pose health risks, with only an additional 300 calories per day needed during the second and third trimesters for the growing fetus.
Step-by-step explanation:
Women who are underweight prepregnancy (BMI < 18.5) are encouraged to gain 28 to 40 pounds in pregnancy. This recommendation considers the importance of adequate weight gain for fetal growth and development. Weight management during pregnancy should support the well-being of both the mother and the developing fetus.
It is a common misconception that a pregnant woman needs to double her caloric intake. In reality, during the second and third trimesters, it is only necessary to consume an additional 300 calories per day to support the growing fetus. Extensive calorie intake beyond this can lead to excessive weight gain, posing risks to both the mother and the baby. Appropriate weight gain supports a healthy birth weight, which is crucial since it influences neonatal health and the risk of chronic diseases later in life.