EPA/600/R-15/169 | December 2015 | www.epa.gov/research Issue Paper on Physiological and Behavioral Changes in Pregnant and Lactating Women and Available Exposure Factors Office of Research and Development Washington, D.C. EPA/600/R-15/169 December 2015 Final www.epa.gov/ncea Issue Paper on Physiological and Behavioral Changes in Pregnant and Lactating Women and Available Exposure Factors National Center for Environmental Assessment Office of Research and Development U.S. Environmental Protection Agency Washington, DC 20460 DISCLAIMER This final document has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. Preferred citation: U.S. Environmental Protection Agency (EPA). (2015) Issue Paper on Physiological and Behavioral Changes in Pregnant and Lactating Women and Available Exposure Factors. National Center for Environmental Assessment, Washington, D.C.; EPA/600/R-15/169. Available from the National Technical Information Service, Springfield, VA and online at http://www.epa.gov/ncea. ii CONTENTS CONTENTS ................................................................................................................................... iii LIST OF TABLES ...........................................................................................................................v LIST OF FIGURES ...................................................................................................................... vii LIST OF ABBREVIATIONS AND ACRONYMS .................................................................... viii PREFACE ........................................................................................................................................x AUTHORS, CONTRIBUTORS, AND REVIEWERS ................................................................. xi EXECUTIVE SUMMARY ......................................................................................................... xiii 1. INTRODUCTION ................................................................................................................... 1-1 1.1. BACKGROUND ......................................................................................................... 1-1 1.2. OBJECTIVES AND SCOPE ....................................................................................... 1-6 1.3. METHODS .................................................................................................................. 1-7 1.4. ORGANIZATION OF THE REPORT ........................................................................ 1-8 1.5. INTENDED AUDIENCE ............................................................................................ 1-8 2. DEFINING THE PREGNANT AND LACTATING LIFESTAGE ........................................ 2-1 3. PHYSIOLOGICAL CHANGES DURING PREGNANCY AND LACTATION .................. 3-1 3.1. CARDIOVASCULAR SYSTEM AND HEMATOLOGICAL SYSTEMS ............... 3-1 3.2. RESPIRATORY SYSTEM ......................................................................................... 3-2 3.2.1. Pulmonary Function, Lung Volume, and Capacities ....................................... 3-2 3.2.2. Respiration ....................................................................................................... 3-3 3.3. RENAL SYSTEM ....................................................................................................... 3-5 3.4. SKELETAL SYSTEM ................................................................................................ 3-6 3.5. NEUROLOGICAL SYSTEM ..................................................................................... 3-7 3.6. DIGESTIVE/GASTROINTESTINAL SYSTEM ....................................................... 3-8 3.7. ENDOCRINE SYSTEM............................................................................................ 3-10 3.7.1. Placenta .......................................................................................................... 3-10 3.7.2. Thyroid Function ........................................................................................... 3-11 3.7.3. Parathyroid Function ...................................................................................... 3-13 3.7.4. Hypothalamic-Pituitary-Adrenal Axis ........................................................... 3-13 3.7.5. Glucose and Carbohydrate Metabolism ......................................................... 3-15 3.7.6. Protein and Lipid Metabolism ....................................................................... 3-16 3.7.7. Metabolic Adjustments .................................................................................. 3-18 3.7.8. Total Body Water Metabolism....................................................................... 3-20 3.8. INTEGUMENTARY SYSTEM ................................................................................ 3-21 3.9. WEIGHT CHANGES ................................................................................................ 3-21 4. BEHAVIORAL ADAPTATIONS AND PSYCHOLOGICAL CHANGES DURING PREGNANCY AND LACTATION ....................................................................................... 4-1 4.1. ADAPTATIONS ......................................................................................................... 4-2 4.1.1. Smoking ........................................................................................................... 4-2 4.1.2. Caffeine Consumption ..................................................................................... 4-4 4.1.3. Alcohol Use ..................................................................................................... 4-4 iii CONTENTS (continued) 4.1.4. Other Adaptations ............................................................................................ 4-6 4.2. DEPRESSION ............................................................................................................. 4-6 4.2.1. Prevalence of Depression ................................................................................. 4-6 4.2.2. Drug Treatment for Depression ....................................................................... 4-7 4.2.3. Factors Impacting Depression in Pregnancy and Lactation ............................. 4-7 4.3. STRESS, ANXIETY, IRRITABILITY, SLEEP, AND FATIGUE ............................ 4-8 4.4. CHANGES IN DIETARY BEHAVIORS ................................................................... 4-9 4.4.1. Nutritional Needs ............................................................................................. 4-9 4.4.2. Energy Requirements ..................................................................................... 4-11 4.4.3. Cravings and Aversions ................................................................................. 4-13 5. EXPOSURE FACTORS FOR PREGNANT/LACTATING WOMEN .................................. 5-1 5.1. WATER INTAKE ....................................................................................................... 5-1 5.2. DIETARY INTAKE .................................................................................................... 5-7 5.3. NONDIETARY INTAKE (PICA)............................................................................. 5-24 5.4. INHALATION RATES ............................................................................................. 5-27 5.5. ACTIVITY FACTORS AND CONSUMER PRODUCT USE ................................ 5-31 5.6. BODY WEIGHT ....................................................................................................... 5-35 6. DATA GAPS ........................................................................................................................... 6-1 7. REFERENCES ........................................................................................................................ 7-1 APPENDIX. COMPARISON OF COMMODITY CONSUMPTION PATTERNS OF PREGNANT AND NONPREGNANT WOMEN OF CHILDBEARING AGE ................... A-1 iv LIST OF TABLES ES-1. Physiological changes during pregnancy by organ system................................................xv ES-2. Physiological changes during lactation by organ system ................................................ xix 1-1. Changes during the first trimester (weeks 1−12) ............................................................. 1-2 1-2. Changes during the second trimester (weeks 13−27) ...................................................... 1-3 1-3. Changes during the third trimester (weeks 28−40) .......................................................... 1-5 2-1. U.S. pregnancy rates for 2008, by age and race (pregnancies per 1,000 women) ........... 2-1 2-2. Percentage of women breastfeeding in 2007 by maternal age and race .......................... 2-3 3-1. Changes in lung volumes and capacities during pregnancy ............................................ 3-4 4-1. Comparison of cigarette, alcohol, and illicit drug use among pregnant and nonpregnant women, aged 15‒44 years, based on the 2009/2010 NSDUH .................... 4-3 4-2. Recommended number of servings for three caloric intake levels for pregnant women ............................................................................................................................ 4-12 5-1. Tapwater and total fluid intake among pregnant, lactating, and control women, based on a 1977‒1978 dietary survey (mL/day)