The Effects of Asymmetric and Symmetric Fetal Growth Restriction on Human Capital Development 公开

Robinson, Joshua (2012)

Permanent URL: https://etd.library.emory.edu/concern/etds/rx913q643?locale=zh
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Abstract


Abstract
The Effects of Asymmetric and Symmetric Fetal Growth Restriction on Human
Capital Development
This study explores the causal pathway by which poor fetal health translates into
reducing educational attainment and earnings as an adult. Using insights from
the medical literature, I decompose low birth weight infants into two distinct
subtypes: a symmetric type, which is characterized by cognitive deficits, and an
asymmetric type, which exhibits little to no cognitive problems. Using data from
a longitudinal survey of newborns, I establish three results: First, there is
empirical evidence of brain sparing in the asymmetric subtype, but not in the
symmetric subtype. Second, despite differences in cognitive impairment, both
subtypes exhibit similar impairment to physical health. And finally, there is
evidence that the causes and timing of onset during pregnancy are different for
asymmetric and symmetric growth restriction. These results indicate that
differentiating between these subtypes may offer new opportunities to identify the
underlying casual relationships between health and human capital development,
as well as uncovering the "black box" mechanism behind the fetal origins
hypothesis. In a separate analysis using Census micro-data and utilizing a
historical "natural experiment", I show that symmetric growth restriction, but not
asymmetric growth restriction, is associated with decreased education and
earnings as an adult. In addition to the academic implications, these results also
have broad implications for the timing of policy interventions aimed at pregnant
women.

Table of Contents

Contents

1 Introduction. . . 1

2 Background. . . 3

2.1 The causes of fetal growth restriction. . . 3

2.2 Economics literature . . . 6

2.3 Medical literature. . . 13

3 Data 16 3.1 Classification of asymmetric and symmetric growth restriction . . . 18 3.2 In-sample classification. . . 20 3.3 Out-of-sample classification . . . 22 4 Testing the Brain Sparing Hypothesis. . . 25 4.1 Methodology. . . 25 4.2 Results. . . 28 4.2.1 OLS results . . . 28 4.2.2 Fixed effects results. . . 29 4.2.3 Standardizing birth weight across sub-types . . . 30 4.2.4 Head circumference and birth weight as a continuous measure. . . 32 4.2.5 Discussion of IQ & IUGR . . . 35

5 Physical Health and IUGR. . . 38

5.1 Methodology. . . 39

5.2 Empirical results . . . 41

6 The Causes of Asymmetric & Symmetric FGR. . . 44

7 The Long-Run Consequences of Asymmetric and Symmetric FGR. . . 47

7.1 The 1918 influenza pandemic . . . 48

7.2 Data. . . 49

7.3 Almond's methodology. . . 51

7.4 Fetal growth restriction. . . 52

7.4.1 Methodology . . . 54

7.4.2 Results. . . 57

7.4.3 Robustness check: New England pandemic. . . 59

7.4.4 Robustness check: World War I Draft. . . 59

7.5 Discussion. . . 62

8 Discussion & Conclusion. . . 63

8.1 Futureresearch . . . 65

List of Figures

  1. IQ distributions broken down by growth type. . . 74

  2. Summary of definitions for different categorizations of the of IUGR . . . 78

  3. Local linear regression for the effects of head circumference IQ . . . 86

  4. The effects of head circumference on IQ by gestational age and birth weight. . . 87

  5. Local linear regression for the effects of birth weight IQ . . . 88

  6. The effects of birth weight on IQ by gestational age and head circumference. . . 89

List of Tables

  1. SummaryStatistics. . . 75

  2. Summary of IUGR variables. . . 76

  3. OLS results for IQ . . . 77

  1. OLS results for IQ at ages 4 and 7 using multiple in-sample def. . . 79

  2. OLS results for IQ at ages 4 and 7 using multiple out-sample def. . . 80

  3. Fixed effects results for IQ . . . 81

  4. Fixed effects results for IQ at ages 4 and 7 using multiple in-sample def. . . 82

  5. Fixed effects results for IQ at ages 4 and 7 using multiple out-sample def. . . 83

  1. Summary of IUGR variables using matched birth weight. . . 84

  2. OLS results for IQ using matched birth weight. . . 85

  3. Rare events logit: congenital malformations . . . 90

  4. Rare events logit: hearing, speech, vision, and seizures. . .91

  5. Matched birth weight rare events logit: congenital malformations . . . 92

  6. Matched birth weight rare events logit: hearing, speech, vision, and seizures . . . 93

  7. Multinomial logit on the causes of IUGR. . . 94

  8. Multinomial logit on the causes of IUGR . . . 95

  9. Sample means, Males. . . 96

  10. Samples means for females . . . 97

  11. Sample means for nonwhite individuals. . . 98

  12. Census results for males, 1919 cohort . . . 99

  13. Census results for females, 1919 cohort . . . 100

  14. Census results for nonwhites, 1919 cohort. . . 101

23. 1960 Census results for males, controlling for birth quarter . . . 102

24. 1960 Census results for males, contolling for birth-state and region. . .103

25. 1960 Census results for females, controlling for birth quarter . . . 103

26. 1960 Census results for females, contolling for birth-state and region. . .104

27. 1960 Census results for nonwhites, controlling for birth quarter. . .104

28. 1960 Census results for nonwhites, contolling for birth-state and region. . . 105

29. 1970 Census results for males, controlling for birth quarter . . .106

  1. 30 1970 Census results for males, contolling for birth-state and region . . .107

  2. 31 1970 Census results for females, controlling for birth quarter . . .108

  3. 32 1970 Census results for females, contolling for birth-state and region . . .109

  4. 33 1970 Census results for nonwhites, controlling for birth quarter . . .110

  5. 34 1970 Census results for nonwhites, contolling for birth-state and region. . . 111

  6. 35 1980 Census results for males, controlling for birth quarter. . . 112

  7. 36 1980 Census results for males, contolling for birth-state and region . . . 113

  8. 37 1980 Census results for females, controlling for birth quarter . . . 114

  9. 38 1980 Census results for females, contolling for birth-state and region. . . 115

  10. 39 1980 Census results for nonwhites, controlling for birth quarter . . . 116

  11. 40 1980 Census results for nonwhites, contolling for birth-state and region . . . 117

  12. 41 1960 Census results for the Eastcoast, controlling for birth quarter . . . 118

  13. 42 1960 Census results for the Eastcoast, contolling for birth-state and region . . . 119

  14. 43 1970 Census results for the Eastcoast, controlling for birth quarter . . 120

  15. 44 1970 Census results for the Eastcoast, contolling for birth-state and region . . . 121

  16. 45 1980 Census results for the Eastcoast, controlling for birth quarter . . 122

  17. 46 1980 Census results for the Eastcoast, contolling for birth-state and region. . . 123

  18. 47 1960 Census results for the South, controlling for birth quarter . . . 124

  1. 48 1960 Census results for the South, contolling for birth-state and region. . . 125

  2. 49 1970 Census results for the South, controlling for birth quarter. . . 126

  3. 50 1970 Census results for the South, contolling for birth-state and region. . . 127

  4. 51 1980 Census results for the South, controlling for birth quarter . . . 128

  5. 52 1980 Census results for the South, contolling for birth-state and region. . . 129

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