Screening, Diagnosis and Management of Gestational Diabetes in New Zealand a Clinical Practice Guideline
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Screening, Diagnosis and Management of Gestational Diabetes in New Zealand A clinical practice guideline 2014 Citation: Ministry of Health. 2014. Screening, Diagnosis and Management of Gestational Diabetes in New Zealand: A clinical practice guideline. Wellington: Ministry of Health. Published in December 2014 by the Ministry of Health PO Box 5013, Wellington 6145, New Zealand ISBN: 978-0-478-44460-5 (online) HP 6087 This document is available at www.health.govt.nz Contents Executive summary xi Scope and purpose of the guideline xv Summary of recommendations xix Chapter 1: Introduction 1 1.1 Epidemiology of gestational diabetes in New Zealand 1 1.2 Adverse outcomes associated with gestational diabetes 2 1.3 Guidelines and position statements 2 1.4 Women’s perspectives on gestational diabetes 2 1.5 Summary 3 Chapter 2: Who should be screened for hyperglycaemia in pregnancy and how? 4 2.1 Background 4 2.2 Prevalence of probable undiagnosed diabetes in New Zealand 4 2.3 Risk factors associated with probable undiagnosed diabetes and gestational diabetes 4 2.4 Screening for undiagnosed diabetes in New Zealand 5 2.5 HbA1c to detect previously undiagnosed diabetes or prediabetes in early pregnancy (< 20 weeks’ gestation) 6 2.6 HbA1c thresholds to identify probable undiagnosed diabetes or prediabetes in pregnant women at less than 20 weeks’ gestation 7 2.7 Screening principles applied to first trimester screening for undiagnosed diabetes 9 2.8 Evidence to recommendations 10 Chapter 3: Screening and diagnosis of gestational diabetes at 24–28 weeks 12 3.1 Background 12 3.2 Systematic review evidence 12 3.3 Optimal diagnostic threshold for maternal and infant outcomes 14 3.4 Risk factor versus universal screening 15 3.5 Evidence to recommendations 17 Chapter 4: Prevention of gestational diabetes 20 4.1 Background 20 4.2 Dietary interventions alone 20 4.3 Exercise interventions alone 21 4.4 Combined dietary and exercise interventions and gestational diabetes diagnosis 21 4.5 Evidence to recommendations 22 Screening, diagnosis and management of gestational diabetes in New Zealand: iii A clinical practice guideline Chapter 5: Treatment for women with gestational diabetes 23 5.1 Background 23 5.2 Combined diet and lifestyle interventions 23 5.3 Exercise versus control 24 5.4 Dietary interventions for gestational diabetes 25 5.5 Oral hypoglycaemics and insulin 26 5.6 Treatment targets for managing glycaemic control in women with gestational diabetes 28 5.7 Ultrasound guided treatment for the management of gestational diabetes 30 5.8 Overall evidence to recommendations for treatment of women with gestational diabetes 31 Chapter 6: Timing of birth in women with gestational diabetes 33 6.1 Background 33 6.2 Mode of birth for women with gestational diabetes 33 6.3 Timing of birth for women with gestational diabetes 34 6.4 Evidence to recommendations 35 Chapter 7: Immediate postpartum care for women and infants 36 7.1 Background 36 7.2 Breastfeeding initiation 36 7.3 Monitoring of neonatal blood glucose levels postpartum 36 7.4 Monitoring of maternal blood glucose levels postpartum 37 7.5 Diabetic medication – oral hypoglycaemics and insulin 37 7.6 Maternal diet 37 7.7 Evidence to recommendations 37 Chapter 8: Information women with gestational diabetes should receive after birth 39 8.1 Background 39 8.2 Breastfeeding 39 8.3 Contraception and family planning 41 8.4 Lifestyle and diet 41 8.5 Evidence to recommendations 42 Chapter 9: Postpartum screening in women diagnosed with gestational diabetes 43 9.1 Background 43 9.2 Systematic review evidence 43 9.3 Diagnostic cohort studies of HbA1c 44 9.4 Interventions to increase postpartum glucose screening in women who had gestational diabetes 44 9.5 Evidence to recommendations 46 iv Screening, diagnosis and management of gestational diabetes in New Zealand: A clinical practice guideline Chapter 10: Type 2 diabetes in women diagnosed with gestational diabetes 48 10.1 Background 48 10.2 Prevalence of type 2 diabetes in women diagnosed with gestational diabetes 48 10.3 Prevalence of type 2 diabetes in early postpartum period (5–16 weeks) 48 10.4 Prevalence of type 2 diabetes (six months to five years) 49 10.5 Prevalence of type 2 diabetes after five or more years’ follow-up 49 10.6 Gestational diabetes as a risk factor for developing type 2 diabetes 49 10.7 Other risk factors associated with developing type 2 diabetes in women diagnosed with gestational diabetes 50 10.8 Summary of evidence 50 Chapter 11: Prevention of type 2 diabetes in women diagnosed with gestational diabetes 52 11.1 Background 52 11.2 Lifestyle interventions 52 11.3 Pharmacological treatment to prevent type 2 diabetes 54 11.4 Ongoing studies 55 11.5 Evidence to recommendations 55 Chapter 12: Cost-effectiveness of screening, diagnosis and treatment of gestational diabetes 56 12.1 Background 56 12.2 Systematic review evidence 56 12.3 Summary of evidence 59 Chapter 13: Interviews with women with gestational diabetes 61 13.1 Interviews with women diagnosed with gestational diabetes 61 13.2 New Zealand health literacy report 64 13.3 Additional evidence on women’s perceptions of gestational diabetes 66 13.4 Summary 68 Chapter 14: Implementation plan 69 14.1 Updating the guideline 70 Chapter 15: Research recommendations 71 References 72 Glossary 89 Screening, diagnosis and management of gestational diabetes in New Zealand: v A clinical practice guideline Appendices 94 Appendix A: Methods and searching 94 Appendix B: Guideline Development Team 106 Appendix C: Clinical questions 107 Appendix D: Maternal and infant outcomes 109 Appendix E: Supporting evidence for Chapter 1 110 Appendix F: Principles of woman-centred care 119 Appendix G: Supporting evidence for Chapter 2 120 Appendix H: Screening principles applied to first trimester screening for undiagnosed diabetes 173 Appendix I: Supporting evidence for Chapter 3 180 Appendix J: Supporting evidence for Chapter 4 192 Appendix K: Supporting evidence for Chapter 5 237 Appendix L: Supporting evidence for Chapter 6 220 Appendix M: Supporting evidence for Chapter 7 222 Appendix N: Supporting evidence for Chapter 9 223 Appendix O: Supporting evidence for Chapter 10 229 Appendix P: Supporting evidence for Chapter 11 238 List of Tables Table A: Ministry of Health recommendations on weight gain in pregnancy 26 Table B: Participants’ knowledge of gestational diabetes 62 Table C: Factors contributing to low screening rates for gestational diabetes 65 Table 1: Percentage of women flagged with gestational diabetes mellitus by ethnicity in New Zealand (2012) 111 Table 2: Summary of appraisals of national and international guidelines using the AGREE II tool 112 Table 3: Risk factors for previously undiagnosed type 2 diabetes 128 Table 4: Risk factors for gestational diabetes identified in clinical guidelines/position statements 132 Table 5: Studies reporting on maternal age as a risk factor for developing hyperglycaemia in pregnancy 135 Table 6: Studies reporting on ethnicity as a risk factor for developing gestational diabetes 140 Table 7: Studies reporting on family history of diabetes as a risk factor for developing gestational diabetes 144 Table 8: Studies reporting on previous history of gestational diabetes as a risk factor for developing gestational diabetes 147 Table 9: Studies reporting on body mass index/weight gain as a risk factor for developing gestational diabetes 150 vi Screening, diagnosis and management of gestational diabetes in New Zealand: A clinical practice guideline Table 10: Studies reporting on macrosomia/large for gestational age as a risk factor for developing gestational diabetes 159 Table 11: Studies reporting on parity as a risk factor for developing hyperglycaemia in pregnancy 161 Table 12: Studies reporting on dietary factors as a risk factor for developing gestational diabetes 163 Table 13: Studies reporting on vitamin D as a risk factor for developing gestational diabetes 166 Table 14: Studies reporting on maternal history of subfertility as a risk factor for developing gestational diabetes 168 Table 15: Recommendations and statements on early screening for diabetes in pregnancy 169 Table 16: Diagnostic accuracy of HbA1c test reported in the Burlingame study (2012) 173 Table 17: Commonly used screening and diagnostic procedures 180 Table 18: Prevalence and characteristics of other screening tests by gestational diabetes diagnostic criteria 187 Table 19: Effect of prevalence on positive and negative predictive values 189 Table 20: Changes in prevalence of gestational diabetes based on diagnostic criteria 190 Table 21: Outcomes for women who would have been diagnosed with gestational diabetes using the International Association of Diabetes and Pregnancy Study Groups’ criteria compared with outcomes for women without gestational diabetes 190 Table 22: Outcomes for women who would have been diagnosed with gestational diabetes using the Carpenter and Coustan criteria compared with outcomes for women diagnosed with gestational diabetes using the National Diabetes Data Group criteria 191 Table 23: Maternal and infant outcomes according to the presence or absence of gestational diabetes and/or at least one risk factor 191 Table 24: Table of effects: dietary interventions to prevent gestational diabetes 192 Table 25: Table of effects: exercise interventions to prevent gestational diabetes 192 Table 26: Table of effects: dietary and exercise interventions to prevent gestational diabetes 193 Table 27: Details of screening/diagnostic criteria of interventions providing specific