BACKGROUND AND PURPOSE:

• Wang et al. (JAMA Network Open, 2021) identified optimal gestational weight gain (GWG) ranges associated with reduced risks of infant morbidity and mortality across maternal BMI categories including the different classes of obesity

METHODS:

• Retrospective cohort study
• Population
  • US nationwide mother infant pairs between 2011 to 2015
  • Data derived from the US National Center for Health Statistics (NCHS) database
• Exposures
  • GWG
• Study design
  • GWG was assessed in 2 kg groups
  • Multivariable logistic regression models were used to link GWG to infant morbidity and mortality and identify optimal GWG ranges for reduced risks of both outcomes
• Primary outcomes
  • Significant morbidity of the newborn infant
    • Presence of assisted ventilation | Admission to NICU | Surfactant therapy | Antibiotic therapy | Seizures
  • Infant mortality <1 year
    • <1 hour | 1 to 23 hours | 1 to 6 days | 7 to 27 days | 28 to 365 days

RESULTS:

• 15,759,945 mother-infant dyads
  • Mean (SD) age: 28.1 (5.9) years
  • GWG mean (SD): 14.1 (7.3) kg
• The mean (SD) GWG decreased with BMI categories (P<0.001)
  • Underweight: 15.7 (6.4) kg
  • Normal weight: 15.4 (6.2) kg
  • Overweight: 14.2 (7.4) kg
  • Obesity class 1: 12.2 (8.0) kg
  • Obesity class 2: 10.3 (8.4) kg
  • Obesity class 3: 8.2 (9.2) kg
• Total significant newborn morbidity: 8.8%
  • Lowest prevalence of morbidity: women in the normal weight BMI class 8.0%
  • Highest prevalence: women with class 3 obesity 12.4%
• Total infant mortality within 1 year of birth: 0.34%
  • Lowest prevalence: women in normal weight class 0.28%
  • Highest prevalence: women with class 3 obesity: 0.58%
• Optimal GWG ranges
  • Underweight and normal weight: 12.0 to <24.0 kg
  • Overweight: 10.0 to <20.0 kg
  • Class 1 obesity: 8.0 to <16.0 kg
  • Class 2 obesity: 6.0 to <16.0 kg
  • Class 3 obesity: 6.0 to <10.0 kg
• Absolute risks of infant morbidity and mortality were lowest in the middle groups of GWG (U-shaped pattern)
  • Infant morbidity most prevalent in the lowest GWG groups among
    • Underweight <8 kg GWG: 14.7%
    • Normal weight women <0 kg GWG: 16.6%
  • Infant morbidity most prevalent in the highest GWG groups among
    • Obesity class 1 ≥30 kg GWG: 15.2%
    • Obesity class 2 ≥20 kg GWG: 13.7%
    • Obesity class 3 ≥20 kg GWG: 17.4%
• Infant mortality
  • Most prevalent in the lowest GWG groups
  • Remained at low levels in middle and high GWG groups across BMI categories

CONCLUSION:

• The lower bounds of the optimal GWG ranges are higher than the existing recommendations for
  • Overweight women: 10.0 vs 7.0 kg
  • Class 1 obesity: 8.0 vs 5.0 kg
  • Class 2 obesity: 6.0 vs 5.0 kg
  • Class 3 obesity: 6.0 vs 5.0 kg
• Women with increasing BMI experienced decreasing rates of GWG
• Inadequate GWG, even for women with obesity, was associated with increased risks of adverse infant outcome
• The authors state

…ranges of optimal GWG generally decreased with BMI categories and the severity of obesity

Recommending a single GWG range (5.0-9.0 kg) for women with obesity may be of concern

… weight maintenance and weight loss should not be used as routine guidelines, even for women with obesity

• Women should not be counseled to maintain or lose weight during pregnancy, regardless of BMI class

Learn More – Primary Sources:

Association of Gestational Weight Gain With Infant Morbidity and Mortality in the United States

Related ObG Topics:

RCT Results: Does Weight Loss Prior to Pregnancy Affect Gestational Weight Gain?

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

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

Recommended Weight Gain and Obesity Management in Pregnancy