Nutrient Needs During Pregnancy

Energy

Energy needs increase during pregnancy for a number of reasons:

• Increased basal metabolic rate due to the metabolic contribution of the uterus and fetus, and the increased work of the heart and lungs
• Products of conception, which include the fetus, placenta and amniotic fluid
• Accretion of maternal tissues, including the uterus, breasts, blood, extracellular fluid, and adipose tissue

This increased energy requirement is not evenly distributed throughout pregnancy. The 2002 Dietary Reference Intakes include guidelines for energy intakes for pregnant women by trimester. For well-nourished women ages 19-50 years the energy needs are listed below:

• 1st trimester - no increase in energy needs
• 2nd trimester - additional 340 kcal per day
• 3rd trimester - additional 452 kcal per day

Note: Energy intakes that promote weight gain in the desired range vary widely because of individual differences in energy expenditure and basal metabolic rate.