BACKGROUND AND PURPOSE:

• Weight gain in excess of current guidelines occurs in 2 out of every 3 pregnancies among women with obesity
• IOM recommends all pregnant women increase energy intake by 340–450 kcal/d during the second and third trimesters
• ACOG acknowledges that obese women may benefit from fewer calories, but no clear guidance is given regarding precise intake
• Most et al. (Journal of Clinical Investigation, 2019) studied energy expediture in women with obesity

METHODS:

• Prospective, observational study
• Participants
  • Pregnant women with obesity (BMI ≥ 30 kg/m² at ≤15 weeks)
• Study design
  • Energy intake was calculated by the energy intake-balance method
  • Energy expenditure in early (13–16 weeks) and late (35–37 weeks) pregnancy was measured by
    • Doubly labeled water
    • Whole-room indirect calorimetry
    • Body composition as a 3-compartment model by air displacement plethysmography
    • Isotope dilution
• Women were grouped in to the following categories
  • Achieved the recommended IOM weight gain: ≥170 g/week to <270 g/week (0.4 to 0.6 lb/week)
  • Excess weight gain: ≥270 g/week
  • Inadequate weight gain: <170 g/week  
• Primary outcomes
  • Energy intake | Energy expenditure | Energy deposition

RESULTS:

• 54 women participated
  • Achieved the recommended IOM weight gain: 15%
    • Energy intake was 125 ± 52 kcal/d less than energy expenditure (i.e. negative energy intake was required to meet the guideline)
  •  Excess weight gain (≥270 g/week): 67%
    • 186 ± 29 kcal/d more than they expended (P < 0.001)
  • Inadequate weight gain (<170 g/week): 19%
    • Inadequate gain was found more often in group with more severe obesity
• No difference in pregnancy outcomes, delivery outcomes, and birth weight among the 3 groups
• Weight gain was not related to
  • Demographics
  • Activity
  • Metabolic biomarkers
  • Diet quality

CONCLUSION:

• This study may be the first to provide the necessary evidence to set energy intake requirements for pregnant women with obesity
• The authors disagree with current IOM guidance that would lead women with obesity to increase energy intake later in pregnancy
  • An energy deficit of approximately 100 kcal/d is required to meet the recommended IOM weight gain recommendations of 0.4 to 0.6 lbs per week
• The authors conclude that

…recommended rate of weight gain was achieved by the gain of fat-free mass alone (e.g., fetus, uterus, blood volume, breast tissue)

…this study challenges current practice and argues that women with obesity should not be advised to consume additional energy during pregnancy as currently recommended.

Learn More – Primary Sources:

Evidence-based recommendations for energy intake in pregnant women with obesity

Related ObG Topics:

Recommended Weight Gain and Obesity Management in Pregnancy

Is There an Association Between High or Low Weight Gain and Maternal and Infant Outcomes?

Can a Smartphone ‘Diet and Activity’ App Impact Gestational Weight Gain?

Does Lifestyle Intervention Ameliorate Pregnancy Weight Gain and Does It Affect Perinatal Outcomes?