Final answer:
The Institute of Medicine recommends no additional calories in the first trimester and an increase of 300 calories per day during the second and third trimesters. This results in an expected weight gain of about 0.45 kg (1 lb) per month in the first trimester and 0.45 kg (1 lb) per week later in pregnancy. It is important to manage weight gain to avoid health risks for the mother and baby.
Step-by-step explanation:
Weight Gain Recommendations for Pregnant Females
The Institute of Medicine (IOM) provides guidelines related to weight gain during pregnancy. In the first trimester, women generally do not need to consume additional calories. A weight gain of about 0.45 kg (1 lb) per month is expected and considered healthy. As the pregnancy progresses into the second and third trimesters, the recommended caloric intake increases by about 300 calories per day, which helps support the rapidly growing fetus. During these later stages, women often gain around 0.45 kg (1 lb) per week.
Excessive caloric intake can lead to too much weight gain, posing risks to both the mother and the baby, such as diabetes and obesity later in the baby's life. Therefore, it's important to focus on healthy weight gain. Pregnancy weight gain is typically seen in the breasts, abdominal region and includes the growing fetus, the expanded uterus, increased blood volume by 30 percent, and respiratory minute volume by 50 percent, with the potential for developing stretch marks and increased melanin production.
Beyond fetal growth, the mother's body prepares for childbirth and breastfeeding, which includes storing an additional approximately 2.3 kg (5 lbs) of fat. A total of around 70,000 Kcal spread over the last two-thirds of pregnancy is typically needed to meet the increased energy demands. This involves additional oxygen consumption and increased energy expenditure due to the extra weight the mother carries during her normal activities.