Final answer:
The average total weight gain for a healthy woman during pregnancy typically ranges between 11.5 kg (25 lbs) and 16 kg (35 lbs), with an increase of about 0.45 kg (1 lb) per week during the second and third trimesters.
Step-by-step explanation:
The average total weight gain during pregnancy for a healthy woman is nuanced and involves different factors such as the growth of the fetus, the enlargement of the uterus, increased blood volume, and growing maternal tissues. Initially, in the first trimester, there is little need for additional caloric intake, with an expected weight gain of about 0.45 kg (1 lb) per month. As pregnancy progresses into the second and third trimesters, the appetite of the expectant mother increases. It is typically sufficient to consume an additional 300 calories per day for supporting the fetus, which is rapidly growing during this period. Overall, a healthy weight gain of about 0.45 kg (1 lb) per week is common in the later stages of pregnancy, particularly during the third trimester when the most substantial growth occurs. This accounts for additional maternal weight from various sources including the fetus, amniotic fluid, and increased breast tissue, not just fat reserves. The total average weight gain throughout a full-term pregnancy is generally between 11.5 kg (25 lbs) and 16 kg (35 lbs).