Brain-Gut Axis and Its Influence on Gestational Weight Gain Restricted; Files Only

Edwards, Sara (Spring 2018)

Permanent URL: https://etd.library.emory.edu/concern/etds/5m60qr91n?locale=en
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Abstract

Abstract

Brain-Gut Axis and Its Influence on Gestational Weight Gain

By Sara Mitchell Edwards

 

Background: Excessive gestational weight gain (GWG) is a significant predictor of adverse obstetric outcomes, postpartum weight retention and lifelong health risks for the woman and infant. In this study I investigated the role of an understudied, but potentially important, biological contributor to maternal obesity and gestational weight gain among AA women: the maternal gut microbiome. 

Purpose: The purpose of this dissertation was to 

· Describe the relationship between maternal gut microbiome composition and interval and total gestational weight gain in AA women.  

· Explore the possible influence of caloric intake, physical activity, and measures of chronic stress on the association between maternal gut microbiome composition and interval and total gestational weight gain in AA women. 

Sample and Design: This was a prospective, longitudinal study of 27 pregnant women enrolled in a larger study investigating biobehavioral determinants of the microbiome and preterm birth in AA women (1R01NR014800).  In this sub-study (1 F31 NR015722-01A1), the participants were enrolled for one additional study visit. Analyses included means, descriptive statistics, ANOVA testing and linear regression modeling to predict the key outcome variables of weight and Firmicutes to Bacteroidetes ratio change during the pregnancy.

Results: The difference in the change in ratio of FTB showed a negative correlation with the ratio at the first time point (r = -.98, p < .001).  Also, the category of weight gain at mid-gestation was associated with change in FTB ratio (f = 3.48, p = .05), with significant difference in FTB ratio between the inadequate versus excessive gainers.  A linear regression model examining the variables of FTB at 1 and ACE-HD explained 25 percent of the variance in the initial weight (Adjusted R square = .25, F (2, 26) = 5.33, p = .01). 

Conclusion: Although interval and total GWG clearly impact obstetric outcomes, and although in non-pregnant populations the gut microbiome and weight gain are closely linked, little research to date has explored the association between the gut microbiome during pregnancy and interval or total GWG. Given the potential to modify the gut microbiome, a better understanding of its contribution to a healthy pregnancy is essential. 

 

Table of Contents

 

Chapter 1: Introduction of Study: Brain-Gut Axis and Its Influence on Gestational Weight Gain 1-34

Figure 1.

Conceptual Framework of Study 18

Table 1. 

Overview of Data Collection for this Study 19

Chapter 2: The Maternal Gut Microbiome during Pregnancy 35-51

Table 1.

Definition of Terms 43

Figure 1. 

The Bidirectional Communication of the Brain-Gut Axis 44

Table 2.  

Recent Relevant Studies of Maternal Gut Microbiome and Maternal/Child Outcomes 45-46

Chapter 3: Maternal Gut Composition and Gestational Weight Gain in African-American Women 52-79

Table 1. 

Overview of Data Collection for this Study 67

Table 2.

Sample Characteristics 68

Table 3.

Weight-Related Characteristics 68

Table 4.

Category of Total Weight Gain by Prenatal BMI Category 69

Table 5.

Correlation Matrix of Significant Associations among Key Variables 69

Figure 1.

FTB Ratio by Category of Total Gestational Weight Gain 70

Table 6.

Firmicutes to Bacteroidetes (FTB) ratio by Initial BMI 70

Table 7.

Firmicutes to Bacteroidetes (FTB) ratio by Weight Gain at mid-gestation (20-25 weeks gestation) 71

Table 8.

Firmicutes to Bacteroidetes (FTB) Ratio by Total Weight Gain in Pregnancy

71

Table 9. 

Firmicutes to Bacteroidetes (FTB) Ratio Change from Time 1 to Time 3 by Initial FTB and Weight Gain Measures 72

Table 10.

Firmicutes to Bacteroidetes (FTB) Ratio Change from Time 1 to Time 3 by Weight Gain Measures 72

Chapter 4: The Brain-Gut Axis and Its Association with Gestational Weight Gain in African-American Women 80-119

Table 1. 

Overview of Data Collection 87

Table 2. 

Measures of Psychosocial Chronic Stress, and Physical Activity 88

Table 3.

Sample Characteristics 100

Table 4.

Weight-Related Characteristics 100

Table 5.

Physical Activity and Daily Kilocalorie Intake 101

Table 6.

Childhood Trauma Questionnaire 101

Table 7.

Adverse Childhood Experiences: Household Dysfunction Score 102

Table 8.

Descriptive Statistics of Dependent and Independent Variables 102

Table 9.

Associations among Independent and Dependent Variables 103

Table 10.

Weight at time 1 by FTB ratio at time 1 and ACE-HD score 104

Table 11.

Total weight gained in pregnancy by FTB ratio at time 1 and ACE-HD score 104

Figure 2.

Associations among Key Variables 105

Chapter 5: Discussion and Conclusion to the Study: Brain-Gut Axis and Its Influence on Gestational Weight Gain 120-147

 

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