Title:

Factors associated with appropriate gestational weight gain among obese women

Authors:

Gabriella D Cozzi, MD¹, Christina T Blanchard, MS^1,2, Macie L Champion, MD¹, Allison Todd, MSN, RN³, Margaret Davis, MPH, RD, CDE^1,3, Paula Chandler-Laney, PhD³, Krista Casazza, PhD, RD³, Brian M Casey, MD¹, Alan Tita MD, MD, PhD¹, Akila Subramaniam, MD, MPH¹

Institutions:

^{Center for Women’s Reproductive Health, Department of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, AL}

^{Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL}

^{Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL}

Background:

• ACOG recommends counseling on appropriate GWG (aGWG) based on pre-pregnancy BMI, advising 11-20 pounds for women with pregestational obesity (defined as >BMI ≥30 kg/m²)
• Pregestational obesity and inappropriate gestational weight gain (iGWG) are independently associated with poor perinatal outcomes, including cesarean section, fetal macrosomia, gestational diabetes and hypertensive disorders
• iGWG occurs in >70% of obese women, and class III obese women (BMI ≥40) are particularly vulnerable
• Unfortunately, achieving appropriate GWG (aGWG) may be limited by socioeconomic status (SES) which can restrict food options, physical activity, and patient support systems
• Although GWG is a modifiable risk factor, standard prenatal care often involves no specific nutritional counseling for obese women
• Factors associated with GWG in obese women have been poorly studied

Objective:

• To compare dietary, exercise patterns, and SES factors among obese women with aGWG versus iGWG

Study Design:

• All pregnant low SES women at our single tertiary care center were offered individualized nutritional counseling (NC) by a registered dietitian between 1/2013-12/2015 as part of a Center for Medicare and Medicaid Services-sponsored Strong Start Study
• NC included education on well-balanced meals using the Department of Agriculture MyPlate guide (Figure) and 150 minutes/week of exercise
• For this study, we performed a retrospective case control study including only obese women (BMI≥30) with a singleton gestation
• Obese women were categorized as aGWG (11-20 pounds) versus iGWG (<11 or >20 pounds)
• aGWG and iGWG were compared with respect to:

• • Attendance of NC (Primary exposure)
  • Dietary composition
  • Activity level
  • SES factors (including education, employment, housing, and family support)

• Chi-square, Fisher’s exact, student’s t-test, and Wilcoxon Rank Sum tests compared exposures between groups as appropriate
• Odds ratios (95% CIs) were calculated with aGWG as the reference group (Tables)
• A subgroup analysis of women with class III obesity (BMI≥40) was planned

Results:

• 411 obese women were analyzed:

• • aGWG: 89 (22%)
  • iGWG: 322 (78%)

• Demographics were similar between groups (Table 1)
• Those with iGWG were

• • Less likely to report physician reinforcement of NC
  • More likely to report inactivity and unemployment
  • There were no differences in food diary compliance, self-reported caloric intake, or dietary composition between groups (Table 2)

• In subgroup analysis of class III obese women, 136 were analyzed (aGWG=30, iGWG=106)
• Those with iGWG were

• • Less likely to attend NC, report physician reinforcement of NC, and have adequate caloric and protein intake
  • More likely to report inactivity
  • There were no differences in SES factors between class III obese groups (Table 3)

Conclusions:

• Among all obese women, physician reinforcement of NC, greater activity level, and employment are associated with aGWG
• Among class III obese women, attendance of NC and dietary modifications are also associated with aGWG
• Given the limited impact of SES factors, enhancing exposure to NC and altering nutritional and exercise choices should be utilized to optimize GWG

Table 1. Maternal Demographics Among Obese Women (BMI≥30) in Strong Start Program

Table 2. Nutritional and Socioeconomic Exposures Among Obese Women (BMI≥30) with Appropriate versus Inappropriate Gestational Weight Gain*

* Data presented as n (%) or median (IQR) as appropriate; aGWG is the reference group

† Individualized dietary caloric needs as determined by registered dietician

** Excessive or inadequate intake was determined using the United States Department of Agriculture MyPlate recommendations, SuperTracker analysis, and Dietary Reference Intakes for pregnancy

Table 3. Nutritional and Socioeconomic Exposures Among Class III Obese Women (BMI≥40) with Appropriate versus Inappropriate Gestational Weight Gain*

* Data presented as n (%) or median (IQR); aGWG is the reference group

† Individualized dietary caloric needs as determined by registered dietician

** Excessive or inadequate intake was determined using the United States Department of Agriculture MyPlate recommendations, SuperTracker analysis, and Dietary Reference Intakes for pregnancy

Figure. MyPlate guide used in Strong Start Program Counseling