GDM Pharmaceutical Management Plan PDF

Queensland Health Clinical Excellence Queensland Maternity and Neonatal Clinical Guideline Gestational diabetes mellitus (GDM) Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) Document title: Publication date: Document number: Document supplement: Amendments: Amendment date: Re...

Queensland Health Clinical Excellence Queensland Maternity and Neonatal Clinical Guideline Gestational diabetes mellitus (GDM) Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) Document title: Publication date: Document number: Document supplement: Amendments: Amendment date: Replaces document: Author: Audience: Review date: Endorsed by: Contact: Gestational diabetes mellitus (GDM) February 2021 MN21.33-V7-R26 The document supplement is integral to and should be read in conjunction with this guideline. Full version history is supplied in the document supplement. Peer review of original document published in August 2015 Amendment May 2022 MN21.33-V6-R26 Queensland Clinical Guidelines Health professionals in Queensland public and private maternity and neonatal services February 2026 Queensland Clinical Guidelines Steering Committee Statewide Maternity and Neonatal Clinical Network (Queensland) Email: [email protected] URL: www.health.qld.gov.au/qcg Cultural acknowledgement We acknowledge the Traditional Custodians of the land on which we work and pay our respect to the Aboriginal and Torres Strait Islander Elders past, present and emerging. Disclaimer This guideline is intended as a guide and provided for information purposes only. The information has been prepared using a multidisciplinary approach with reference to the best information and evidence available at the time of preparation. No assurance is given that the information is entirely complete, current, or accurate in every respect. The guideline is not a substitute for clinical judgement, knowledge and expertise, or medical advice. Variation from the guideline, taking into account individual circumstances, may be appropriate. This guideline does not address all elements of standard practice and accepts that individual clinicians are responsible for: • • • • • • • Providing care within the context of locally available resources, expertise, and scope of practice Supporting consumer rights and informed decision making, including the right to decline intervention or ongoing management Advising consumers of their choices in an environment that is culturally appropriate and which enables comfortable and confidential discussion. This includes the use of interpreter services where necessary Ensuring informed consent is obtained prior to delivering care Meeting all legislative requirements and professional standards Applying standard precautions, and additional precautions as necessary, when delivering care Documenting all care in accordance with mandatory and local requirements Queensland Health disclaims, to the maximum extent permitted by law, all responsibility and all liability (including without limitation, liability in negligence) for all expenses, losses, damages and costs incurred for any reason associated with the use of this guideline, including the materials within or referred to throughout this document being in any way inaccurate, out of context, incomplete or unavailable. Recommended citation: Queensland Clinical Guidelines. Gestational diabetes mellitus (GDM). Guideline No. MN21.33-V6-R26. Queensland Health. 2022. Available from: http://health.qld.gov.au/qcg © State of Queensland (Queensland Health) 2022. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives V4.0 International licence. In essence, you are free to copy and communicate the work in its current form for non-commercial purposes, as long as you attribute Queensland Clinical Guidelines, Queensland Health and abide by the licence terms. You may not alter or adapt the work in any way. To view a copy of this licence, visit https://creativecommons.org/licenses/by-nc-nd/4.0/deed.en For further information, contact Queensland Clinical Guidelines, RBWH Post Office, Herston Qld 4029, email [email protected]. For permissions beyond the scope of this licence, contact: Intellectual Property Officer, Queensland Health, GPO Box 48, Brisbane Qld 4001, email [email protected] Refer to online version, destroy printed copies after use Page 2 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) Flow Chart: Screening and diagnosis of GDM Risk factors for GDM • BMI > 30 kg/m2 (pre-pregnancy or on entry to care) • Ethnicity (Asian, Indian subcontinent, Aboriginal, Torres Strait Islander, Pacific Islander, Maori, Middle Eastern, non-white African) • Previous GDM • Previous elevated BGL • Maternal age ≥ 40 years • Family history DM (1st degree relative or sister with GDM) • Previous macrosomia (birth weight > 4500 g or > 90th percentile • Previous perinatal loss • Polycystic ovarian syndrome • Medications (corticosteroids, antipsychotics) • Multiple pregnancy Assess all women for risk factors Post bariatric surgery? Yes No No Risk factors? Yes First trimester 2 hour 75 g OGTT (or HbA1c) 24-28 weeks gestation 2 hour 75 g OGTT No OGTT (or HbA1c) abnormal? Yes OGTT normal? No Yes Routine antenatal care GDM care OGTT not suitable/tolerated First trimester • If diabetes history or risk factors– fasting BGL or HbA1c Second trimester • 24–28 weeks fasting BGL • If BGL 4.6–5 mmol/L, commence fasting and postprandial capillary BGL self monitoring for 1–2 weeks o Suggested targets: § Fasting < 5 mmol/L § 1 hour post prandial ≤ 7.4 mmol/L § 2 hours post prandial ≤ 6.7 mmol/L Third trimester • If clinical suspicion of diabetes (e.g. evidence of excess fetal growth/adiposity on growth USS), repeat testing GDM diagnosis HbA1c first trimester only • ≥ 41 mmol/mol (or 5.9%) OGTT one or more of: • Fasting ≥ 5.1 mmol/L • 1 hour ≥ 10 mmol/L • 2 hour ≥ 8.5 mmol/L BGL: blood glucose level BMI: body mass index DM: diabetes mellitus GDM: gestational diabetes mellitus HbA1c: glycated haemoglobin OGTT: Oral glucose tolerance test ≥: greater than or equal to >: greater than; ≤ less than or equal to *Post malabsorptive bariatric surgery includes Roux-en-Y, laparoscopic sleeve gastrectomy, bilio-pancreatic diversion with duodenal switch; does not include adjustable gastric banding Flowchart: F21.33-1-V9-R26 Refer to online version, destroy printed copies after use Page 3 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) Flow Chart: Intrapartum management of women with GDM requiring metformin and/or insulin GDM Insulin or metformin Mode of birth? Vaginal (spontaneous or IOL) Elective CS Metformin • Cease when labour established Day before procedure • Cease metformin after evening dose prior to procedure • Give usual insulin the night before procedure Insulin • Cease when labour established • If morning IOL (and labour not established) o Eat breakfast and give usual rapid acting Insulin o Omit morning long or intermediate acting Insulin • If afternoon IOL (and labour not established) o Give usual mealtime and bedtime insulin • If IV insulin infusion consult before ceasing Day of morning procedure • Fast for 6 hours • When fasting omit sub-cut insulin • If insulin infusion consult with anaesthetist Monitor BGL 2/24 4.0─7.0 Hypoglycaemia signs and symptoms • Hunger • Palpitations, dizziness, sweating • Headache, irritability • Tingling around lips, fingers • Blurred vision • Confusion/lack of concentration • Behaviour changes • Loss of consciousness BGL result? (mmol/L) > 7.0 Hyperglycaemia • Review clinical circumstances (e.g. stage of labour, intake) Option 1: • Repeat BGL in 1 hour and reassess requirements Option 2: • Consider insulin infusion < 4.0 Hypoglycaemia • Cease insulin therapy • If symptomatic: o Treat hypoglycaemia and repeat BGL in 15 minutes • If asymptomatic and receiving insulin: o Repeat BGL in 15 minutes and reassess • If asymptomatic and not receiving insulin: o Repeat BGL in 1 hour and reassess (or earlier if symptoms develop) • Review clinical circumstances (e.g. stage of labour, intake) BGL: blood glucose level CS: caesarean section GDM: gestational diabetes mellitus IOL: induction of labour IV: intravenous OGTT: oral glucose tolerance test QCG: Queensland Clinical Guidelines subcut: subcutaneous <: less than >: greater than Flowchart: F21.33-2-V2-R26 Refer to online version, destroy printed copies after use Page 4 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) Flow Chart: Postpartum care of women with GDM All GDM Yes Pharmacological therapy? No Insulin or metformin No Pharmacological therapy Cease metformin and/or insulin immediately after birth (vaginal or CS) Cease BGL monitoring after birth BGL monitoring • Target BGL ≤ 8.0 mmol/L • Monitor BGL 4 times per day for 24 hours after birth (preprandial and before bed) • If all preprandial BGL 4─8 mmol/L, cease monitoring 24 hours after birth BGL < 4.0 mmol/L • If BGL < 4.0 mmol/L or diet not tolerated o Seek medical review o Consider IV fluid 12 hourly BGL > 8.0 mmol/L • If any preprandial BGL > 8.0 mmol/L o Seek medical review o Continue BGL monitoring • Insulin rarely required postpartum o If indicated, prescribe lower dose than required during pregnancy IV therapy (if any) • If BGL ≥ 4.0 mmol/L and diet tolerated cease mainline IV fluids after birth Postpartum care Postpartum • All routine care as indicated Breastfeeding • Women with GDM are less likely to BF and to BF for shorter duration • Support and encourage BF with advice, information and skilled lactation support • Metformin and insulin are safe when BF Care of baby • Keep warm • Early feeding within 30─60 minutes of birth • Monitor and manage baby’s BGL • Refer to QCG Newborn hypoglycaemia Discharge • Consider routine criteria to inform readiness for discharge • Advise of benefits of optimising postpartum and inter-pregnancy weight • Recommend OGTT at 6─12 weeks postpartum to screen for persistent diabetes • Recommend lifelong screening for diabetes at least every 3 years • Recommend early glucose testing in future pregnancy BGL: blood glucose level BF: breast feed CS: caesarean section GDM: gestational diabetes mellitus IV: intravenous OGTT: oral glucose tolerance test QCG Queensland Clinical Guidelines QID 4 times per day subcut: subcutaneous >: greater than ≥: greater than or equal to <: less than ≤: less than or equal to Flowchart: F21.33-3-V2-R26 Refer to online version, destroy printed copies after use Page 5 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) Table of Contents Abbreviations ......................................................................................................................................... 7 Definitions .............................................................................................................................................. 8 1 Introduction ..................................................................................................................................... 9 1.1 1.2 1.3 2 Prevalence ...................................................................................................................................................9 Diabetes classification ................................................................................................................................10 Clinical standards .......................................................................................................................................11 Risk assessment .......................................................................................................................... 12 2.1 Risk factors.................................................................................................................................................12 2.2 Risk reduction .............................................................................................................................................12 2.3 Risks from GDM .........................................................................................................................................13 2.3.1 Maternal risks from GDM .......................................................................................................................13 2.3.2 Fetal baby risks from GDM ....................................................................................................................14 3 Diabetes diagnosis ....................................................................................................................... 15 3.1 3.2 3.3 3.4 4 Antenatal care .............................................................................................................................. 18 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.8.1 5 Metformin ...................................................................................................................................................27 Insulin therapy ............................................................................................................................................28 Insulin type by glycaemic abnormality ....................................................................................................28 Hypoglycaemia ...........................................................................................................................................29 Education for safe self-administration of insulin therapy .............................................................................30 Birthing ......................................................................................................................................... 31 6.1 6.1.1 6.2 6.3 6.4 6.4.1 7 Antenatal care ............................................................................................................................................18 Maternal care .............................................................................................................................................19 Special considerations ................................................................................................................................20 Fetal surveillance........................................................................................................................................21 Psychosocial support and education ..........................................................................................................22 Self-monitoring ...........................................................................................................................................23 Medical nutrition therapy.............................................................................................................................24 Physical activity ..........................................................................................................................................25 Physical activity cautions and contraindications .....................................................................................26 Pharmacological therapy .............................................................................................................. 27 5.1 5.2 5.2.1 5.3 5.4 6 Diagnostic tests ..........................................................................................................................................15 Testing for GDM .........................................................................................................................................16 Diagnosis of GDM or diabetes in pregnancy...............................................................................................17 Diagnostic BGL...........................................................................................................................................17 Considerations for birth...............................................................................................................................31 Birth .......................................................................................................................................................32 Pharmacotherapy as birth approaches .......................................................................................................33 Intrapartum monitoring ...............................................................................................................................33 Intrapartum BGL management ...................................................................................................................34 Insulin infusion .......................................................................................................................................34 Postpartum care ........................................................................................................................... 35 7.1 7.2 Breastfeeding .............................................................................................................................................36 Discharge planning .....................................................................................................................................37 References .......................................................................................................................................... 38 Appendix A: Conversion table for HbA1c measurement ..................................................................... 43 Appendix B: Gestational weight gain ................................................................................................... 43 Appendix C: Antenatal schedule of care ............................................................................................. 44 Appendix D: Exercise and exertion ..................................................................................................... 45 Acknowledgements .............................................................................................................................. 46 Refer to online version, destroy printed copies after use Page 6 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) List of tables Table 1. Diabetes classification ........................................................................................................... 10 Table 2. Clinical standards .................................................................................................................. 11 Table 3. GDM risk factors .................................................................................................................... 12 Table 4. Risk reduction ........................................................................................................................ 12 Table 5. Maternal risks ........................................................................................................................ 13 Table 6. Fetal/baby risks...................................................................................................................... 14 Table 7. Diagnostic tests ..................................................................................................................... 15 Table 8. Testing for GDM .................................................................................................................... 16 Table 9. Diabetes diagnosis ................................................................................................................ 17 Table 10. Blood glucose level for diagnosis ........................................................................................ 17 Table 11. Antenatal care...................................................................................................................... 18 Table 12. Maternal care ....................................................................................................................... 19 Table 13. Special considerations ......................................................................................................... 20 Table 14. Fetal surveillance ................................................................................................................. 21 Table 15. Psychosocial support and education ................................................................................... 22 Table 16. Self-monitoring..................................................................................................................... 23 Table 17. Medical nutrition therapy ..................................................................................................... 24 Table 18. Physical activity ................................................................................................................... 25 Table 19. Physical activity cautions and contraindications.................................................................. 26 Table 20. Metformin ............................................................................................................................. 27 Table 21. Insulin therapy ..................................................................................................................... 28 Table 22. Insulin type by glycaemia abnormality ................................................................................. 28 Table 23. Hypoglycaemia in women receiving glucose lowering medication...................................... 29 Table 24. Education for safe self-administration of insulin .................................................................. 30 Table 25. Considerations for birth ....................................................................................................... 31 Table 26. Birth ..................................................................................................................................... 32 Table 27. Pharmacotherapy as birth approaches ............................................................................... 33 Table 28. Intrapartum monitoring ........................................................................................................ 33 Table 29. Intrapartum BGL monitoring ................................................................................................ 34 Table 30. Example insulin infusion ...................................................................................................... 34 Table 31. Postpartum BGL monitoring ................................................................................................ 35 Table 32. Breastfeeding....................................................................................................................... 36 Table 33. Discharge planning .............................................................................................................. 37 Abbreviations AC ADIPS BGL BMI CI CS EFW GDM GI GWG HbA1c IFG IGT IOL LGA MNT NDSS OGTT PCOS SGA USS Abdominal circumference Australasian Diabetes in Pregnancy Society Blood glucose level Body mass index Confidence interval Caesarean section Estimated fetal weight Gestational diabetes mellitus Glycaemic index Gestational weight gain Glycated haemoglobin Impaired fasting glucose Impaired glucose tolerance Induction of labour Large for gestational age Medical nutrition therapy National Diabetes Services Scheme Oral glucose tolerance test–75 gram glucose load Polycystic ovarian syndrome Small for gestational age Ultrasound scan Refer to online version, destroy printed copies after use Page 7 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) Definitions Antenatal contact Anti-insulin antibodies Dumping syndrome In this guideline the term antenatal contact includes all forms of interaction between the pregnant woman and her care providers for the purpose of providing antenatal care. For example, telephone consults or SMS messaging, email, home visits, scheduled hospital appointments, videoconference or telehealth discussions. Autoimmune marker of diabetes mellitus. Also known as postprandial syndrome. See below. Gestational diabetes mellitus In this guideline the term ‘GDM’ is used to refer to women with diagnostic criteria for both GDM and Diabetes in Pregnancy unless otherwise specified. Refer to Table 1. Diabetes classification. Glutamic acid decarboxylase antibodies (GADA) Autoimmune marker of diabetes mellitus Impaired fasting glucose (IFG) Impaired glucose tolerance (IGT) Islet antigen-2 antibodies (IA-2A) Large for gestational age (LGA) Macrosomia Multidisciplinary team Postprandial syndrome Pre/postprandial Pre-diabetes Psychosocial services Small for gestational age (SGA) Suspected fetal macrosomia Diagnosed when the fasting BGL is higher than the normal range, but does not rise abnormally after a 75 gram glucose drink. Included in the definition of ‘pre-diabetes’. BGL at 2 hours during an OGTT (oral glucose tolerance test) is higher than the normal range, but not high enough to diagnose type 2 diabetes. Included in the definition of ‘pre-diabetes’. Autoimmune marker of diabetes mellitus. Fetal weight greater than the 90th percentile for gestational age. Consider parental ethnicity and anthropometry.1 Birth weight greater than 4500 g.1 May include midwife, nurse practitioner, endocrinologist, obstetric physician, physician, dietitian, obstetrician, credentialled diabetes educator, general practitioner (GP), GP obstetrician, paediatrician/neonatologist, lactation consultant, Indigenous health worker, exercise physiologist or other health professional as appropriate to the clinical circumstances. Occurs within 60 minutes of ingestion of food, usually rapidly absorbed carbohydrates resulting in dizziness, flushing and palpitations. Also called dumping syndrome. Before/after eating a meal. Blood glucose levels are higher than normal, but not at a level to diagnose type 2 diabetes. Includes impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). Any services, organisation (government or non-government) or health discipline that provides counselling, support, mental wellbeing assessment, psychiatric care, peer support, or other psychological or psychosocial care. Birth weight below the 10th percentile1, not necessarily implying fetal growth restriction as baby may be constitutionally small. Ultrasound scan estimated fetal weight and/or abdominal circumference greater than 95th percentile for gestation.2 Refer to online version, destroy printed copies after use Page 8 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 1 Introduction Gestational diabetes mellitus (GDM) is one of the most common medical complications of pregnancy.3-5 It is defined as glucose intolerance that is first diagnosed or recognised during pregnancy, and does not meet criteria for overt diabetes outside pregnancy. If glucose levels are high enough to be consistent with a diagnosis of diabetes outside pregnancy, the term ‘Diabetes in Pregnancy’ (DIP) is preferred. DIP commonly represents undiagnosed diabetes mellitus detected for the first time during pregnancy6,7, but the diagnosis generally requires confirmation in the postpartum period. Although GDM usually resolves following birth, it is associated with significant morbidities for the woman and baby in the perinatal period, and in the long term.5,8-17 There is widespread (but not universal) consensus on the diagnostic criteria for GDM used in this guideline. This includes endorsement by a significant number of professional organisations including Australasian Diabetes in Pregnancy Society (ADIPS)7, National Health and Medical Research Council18, Australian College of Midwives, International Association of Diabetes and Pregnancy Study Group19, Australian Diabetes Educators Association, The Royal Australian and New Zealand College of Obstetricians and Gynaecologists20, The International Federation of Gynecology and Obstetrics21 and the World Health Organisation.4 1.1 Prevalence The number of women diagnosed with GDM is increasing. This may reflect the increase in both maternal age and body mass index (BMI) of the pregnant population, and/or be associated with changing definitions of GDM.22 • Queensland incidence of GDM (as at January 31 2020) was 13% in 201823 • Australian incidence of GDM was 14% of women birthing in hospital in 201822 • Incidence of GDM has tripled since 2000–200122 o The incidence of GDM increases with the level of socioeconomic disadvantage (21% compared with 13%)24 • Incidence of GDM for Aboriginal and/or Torres Strait Islander women was similar to the rate in non-Indigenous women (adjusted for differences in age structure of each group)22 • Older women (45–49 years) were more than four times likely to have a GDM diagnosis24 • Treatment in 2016–2017: o 32% required insulin therapy24 o 8% required oral hypoglycaemia medications24 Refer to online version, destroy printed copies after use Page 9 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 1.2 Diabetes classification Table 1. Diabetes classification Classification Description • Glucose intolerance with onset or first recognition during pregnancy GDM4,6 • Elevated plasma glucose levels less severe than overt diabetes • Refer to Table 10. Blood glucose level • Hyperglycaemia onset or first recognition during pregnancy • Plasma glucose levels exceed the threshold(s) for diagnosis of diabetes outside pregnancy • May indicate undiagnosed or pre-existing diabetes outside pregnancy, but Diabetes in a definitive diagnosis of non-gestational diabetes cannot be made until the 4,6 pregnancy postpartum period • Additional management (beyond that required for lower abnormal plasma glucose levels) is required • Refer to Table 10. Blood glucose level • The body no longer makes its own insulin and cannot convert glucose into energy, resulting from β cell destruction that leads to near or absolute insulin deficiency • Commonly accompanied by autoimmune markers including anti-GAD, *Type 14,6 anti-IA-2A antibodies and anti-insulin antibodies • Daily insulin via injection or a continuous subcutaneous insulin infusion (CSII) pump is required • Diagnosis is usually established outside of pregnancy (before or after) • Hyperglycaemia resulting from insulin resistance and/or insufficient production of insulin • Lifestyle modification (diet and physical activity) is the cornerstone of management • Oral hypoglycaemic medication and/or insulin therapy is usually required • If woman is on non-insulin injectables (e.g. GLP1 agonists) these are *Type 26 ceased at pregnancy diagnosis, due to lack of safety data for use during pregnancy • Diagnosis is usually established outside of pregnancy (before or after) or may present as diabetes in pregnancy (confirm diagnosis postpartum) o Elevated HbA1c in first trimester [refer to Table 10. Blood glucose level for diagnosis] • A condition in which blood glucose levels are higher than normal but not high enough to be diagnostic of diabetes *Pre-diabetes6,25 • Includes impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) • Diagnosis is established outside of pregnancy (before or after) *Management not discussed in this guideline Refer to online version, destroy printed copies after use Page 10 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 1.3 Clinical standards Table 2. Clinical standards Aspect Clinical care Model of care Diabetes related products Consideration • Develop locally agreed protocols to support management including26: o Consultation mechanisms, or processes with higher service capabilities including the use of telehealth o Standardised forms or communications that support care planning (e.g. peripartum insulin management plan) o Mechanisms for offering dietary advice, blood glucose monitoring and blood glucose lowering therapy as indicated • Support clinical staff to develop communication skills that enable positive and non-judgemental discussions about obesity and weight gain with pregnant women27 • Consider access to local resources (e.g. anaesthetic services, dietetic services, consulting rooms) • Refer to QCG Standard care guideline28 • Individualise care for the woman18 o Provide common philosophy involving shared understanding of care pathways by all health care providers involved in the women’s care18,29 o Collaborative model of care that supports continuity of midwifery care improves maternal and neonatal outcomes and is suitable for high risk women30,31 • Establish referral pathways and consultation mechanisms with higher level services as required32 o Establish local criteria for low risk GDM model of care: o Consider local experience and expertise in management of GDM, as well as criteria that prompts a review or signals that a change in model of care may be required • The following groups of women are not suitable for care in a low risk model: o Pre-existing diabetes (type 1 or type 2) o Diagnosis of diabetes in pregnancy o GDM requiring pharmacological therapy o GDM with other medical or pregnancy complications • A multidisciplinary team approach is ideal33,34 [refer to Definitions] • Women with well managed diet controlled GDM and no other risk factors for known complications, may be suitable for low risk models of care although closer surveillance/more frequent antenatal contact is still required • Midwifery31 and general practitioner (GP) continuity of care models compliment high risk obstetric care • Increased breastfeeding rates have been reported in women with diabetes in pregnancy who receive consistent support35 • Establish access to free or subsidised blood glucose meter programs (e.g. via manufacturers) • Advise to register (requires approved clinician support) with National Diabetes Services Scheme (NDSS)36 to access diabetes related products at subsidised cost o Free registration is open to all Australian citizens and others who are Medicare eligible36 o Registration with National Gestational Diabetes Register aids accurate national data collection, and creates a recall system for women and their GP about the importance of postnatal oral glucose tolerance test (OGTT), and ongoing surveillance for type 2 diabetes Refer to online version, destroy printed copies after use Page 11 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 2 Risk assessment Abnormalities of glucose tolerance have immediate, short-term, and long-term implications for the health of the woman and her baby24, and may be prevented by adequate treatment.6,14 Discuss with all women the benefits of achieving or maintaining a healthy lifestyle (e.g. nutrition, gestational weight gain and physical activity).14,26 2.1 Risk factors Assess all women early in their pregnancy for risk factors associated with gestational diabetes.7 Table 3. GDM risk factors Aspect Risk factors Context • It is not known if all risk factors are of equivalent predictive value7 • Greater risk for women who are: o Asian o Indian subcontinental (India, Pakistan, Bangladesh, Nepal, Sri Lanka, Bhutan, and the Maldives) o Aboriginal and/or Torres Strait Islander o Pacific Islander o Maori o Middle Eastern o Non-white African • Previously elevated blood glucose level1,7,12 or previous GDM1,12,37,38 • Maternal age greater than or equal to 40 years 7,37 • Obesity (BMI greater than 30 kg/m2)1,7,12,14,37 • Family history of diabetes mellitus (first degree relative with diabetes or sister with GDM)1,14,37 • Previous large for gestational age (LGA) baby7 [refer to Definitions] • Polycystic ovarian syndrome1,7,12,37 • Previous perinatal loss1,7,12,14,37 • Medications–corticosteroids1,12, antipsychotics7 • Multiple pregnancy39 Ethnicity1,7,37 Maternal history 2.2 Risk reduction Table 4. Risk reduction Aspect Context Recommendation Consideration • Incidence of GDM may be reduced by lifestyle interventions started before the 15th week of pregnancy (RR 0.80, 95% CI 0.66–0.97) when compared to standard care40 o Not effective for women later in pregnancy40 • Probiotics have not shown any proven role in GDM prevention in pregnant women who are overweight or have obesity41 • Low vitamin D levels: o Have been associated with increased risk of developing GDM o Have been associated with sub-optimal blood glucose levels (BGL) in women with GDM in third trimester15 o Require supplementation in women from populations at risk to reduce the risk of GDM42,43 o If woman has a low baseline vitamin D (less than 50 nmol/L) supplementation may reduce the risk of GDM44 • It is unclear if physical activity interventions/exercise during pregnancy prevent GDM, but they do limit excessive gestational weight gain (GWG), and reduce the risk of caesarean birth and of having a LGA baby45,46 • Advise women that regular physical activity and healthy eating before and during pregnancy help to limit excessive weight gain47 Refer to online version, destroy printed copies after use Page 12 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 2.3 Risks from GDM 2.3.1 Maternal risks from GDM Table 5. Maternal risks Aspect Context Maternal short term risks Maternal long term risks Consideration • There is a clear relationship between increased plasma glucose levels during pregnancy, and adverse maternal and fetal outcomes independent of other known factors for these outcomes5,8,48 • Continuum of risk for adverse pregnancy outcomes is across maternal glucose levels and includes levels below diagnostic values for GDM4,8,49 • There is variable quality and conflicting evidence about the degree of risk conferred by maternal hyperglycaemia on maternal and fetal outcomes50 • Pre-eclampsia8,12,14,24,48 • Induced labour24,48 • Operative birth12,15,24 • Hypertension in pregnancy24 • Caesarean section24,48 • Preterm labour and birth24 • Polyhydramnios51 • Post-partum haemorrhage51 • Infection51 • Birth trauma • Recurrent GDM in subsequent pregnancies52,53 o Magnitude of risk increased with the number of prior pregnancies with GDM o Increased risk of developing GDM in second pregnancy (OR, 13.2; 95% CI, 12.0–14.6)54 o Rate of GDM in second and third pregnancies 4.2–4.7%54 • Progression to type 2 diabetes11,15 o About 5–6.5% within 6 months of birthing55 o 10.7% if untreated [OR 7.63; 95% CI, 5.33–10.95]5 • Risk of developing diabetes or pre-diabetes at mean of 11.4 years post GDM affected pregnancy11 o 52.2% (OR 3.44, 95% CI, 2.85 to 4.14) • Increased risk of developing a disorder of glucose metabolism11 (e.g. IFG, IGT or type 2 diabetes) • Development of metabolic syndrome48 • Development of cardiovascular disease15,56 • Renal disease56 Refer to online version, destroy printed copies after use Page 13 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 2.3.2 Fetal baby risks from GDM Table 6. Fetal/baby risks Aspect Fetal/newborn baby short term risks Baby long term risks Consideration • Prematurity8,15, especially if maternal hyperglycaemia severe and required treatment with insulin13 • Macrosomia8,12,15-17 especially if maternal hyperglycaemia severe and required treatment with insulin13,16,48 • Increased newborn weight8,57 and adiposity57 • Birth trauma—risk increases as fetal growth accelerates and weight increases8,12,16,17 o Bone fracture o Nerve palsy • Hypoglycaemia8,15 • Respiratory distress syndrome15,17 • Jaundice8,16 • Hypocalcaemia15 • Polycythaemia/hyperviscosity58 • Cardiac anomalies including hypertrophic cardiomyopathy and consequent left ventricular outflow tract obstruction59 • Stillbirth (late) if GDM is uncontrolled or not treated resulting in raised fasting plasma glucose60 • Increased risk for: o Impaired glucose tolerance15 o Development of type 2 diabetes15 o Overweight and obesity5,11,15,61 • Insufficient evidence for which strategy for management of diabetes in pregnancy reduces long term risks for the baby62 Refer to online version, destroy printed copies after use Page 14 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 3 Diabetes diagnosis 3.1 Diagnostic tests Table 7. Diagnostic tests Aspect Context OGTT HbA1c Plasma glucose Test type recommendation Consideration • Use a single set of diagnostic criteria for GDM and diabetes in pregnancy [refer to Table 10. Blood glucose level for diagnosis] • Some professional bodies recommend using non-pregnancy glucose reference ranges in first trimester—not endorsed by ADIPS7 • Not all women with mild elevations of glucose (particularly fasting glucose) in early pregnancy will progress to severe glucose abnormalities63 o Individualised management is required • Main value is to identify women with any degree of hyperglycaemia19 • Suitable for use in the first trimester and at 24–28 weeks gestation o There is lack of evidence based targets for first trimester to diagnose GDM14 • Diagnosis by OGTT results in better perinatal outcomes (e.g. LGA, neonatal unit admissions and neonatal hypoglycaemia) when compared with the two step glucose challenge test64 • HbA1c is only suitable in first trimester for women with risk factors18, before erythrocyte formation starts to increase and basal glucose levels fall • Limited use for GDM diagnosis, management or postpartum assessment7 because of low test sensitivity o Unlikely to identify women with milder degrees of hyperglycaemia, GDM or reflect rapidly developing insulin resistance o Only useful if woman also has fasting plasma glucose level (PGL) as each has a different sensitivity for GDM diagnosis • Known haemoglobinopathy may underestimate HbA1c due to increased red cell turnover65 • Main value is to identify women likely to have pre-existing glucose abnormalities (e.g. type 2 diabetes) • Refer to Appendix A: Conversion table for HbA1c measurement • Fasting (8–12 hours after eating) is used as it is less influenced by time and recent food intake66 • Fasting PGL at 24–28 weeks gestation only recommended as suggested below* • OGTT is the preferred diagnostic test for pregnant women with or without risk factors7 • *During COVID-19 pandemic a modified two step testing protocol67 was implemented to reduce community exposure risk, but requires further evaluation before adoption as standard care: o If fasting PGL § Less than 4.7 mmol/L, normal result § 4.7–5.0 mmol/L OGTT indicated § Greater than 5 mmol/L, diagnostic of GDM • There may be circumstances where HbA1c and fasting blood glucose are appropriate in the first trimester including: o Woman is at high risk of underlying type 2 diabetes (e.g. Aboriginal and/or Torres Strait Islander) o If the woman is unable to tolerate the OGTT (e.g. due to morning sickness, hyperemesis) o Opportunistic care is appropriate due to potential for woman declining or unable to complete OGTT o OGTT is not practical due to clinical, geographical or logistical circumstances o May be suitable for women who have had bariatric surgery and are at risk of postprandial syndrome (“dumping syndrome”)68 o Woman is taking metformin for polycystic ovarian syndrome (PCOS)69 Refer to online version, destroy printed copies after use Page 15 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 3.2 Testing for GDM Offer all women for GDM during pregnancy as outlined in Table 8. Testing for GDM. The oral glucose challenge test is no longer recommended.4,7,19-21 Table 8. Testing for GDM Aspect Context With risk factor(s) Post-bariatric surgery No risk factor(s) Maternal medications* If OGTT declined Consideration • Advise the woman having an OGTT to66,70: o Maintain a normal diet o Fast for 8–14 hours before the OGTT o Drink water during fasting to prevent dehydration o Continue any usual medications [refer to Maternal medications* below] • Perform an early OGTT (or HbA1c) with first antenatal bloods or at the first antenatal visit (in the first trimester)7,19 • If the early OGTT (or HbA1c) is normal, repeat OGTT at 24–28 weeks gestation as for women with no risk factors19 • If woman has had laparoscopic adjustable gastric banding (LAGB) or sleeve gastrectomy (SG) o Usual GDM testing68 may be possible o OGTT at 24–28 weeks gestation o If gastric band is tight or the woman is vomiting, OGTT unlikely to be tolerated • If post malabsorptive BS (e.g. Roux-En-Y gastric bypass (RYGB), or biliopancreatic diversion)68 an OGTT is not suitable due to altered gastric emptying including postprandial syndrome (“dumping syndrome”)68 • In first trimester consider: o If history of diabetes or other risk factors68,71, a fasting BGL and HbA1c o If HbA1c greater than or equal to 48 mmol/mol (6.5%), or fasting BGL is greater than or equal to 7.0 mmol/L71 treating woman as if has type 2 diabetes o If history of diabetes, repeat HbA1c71 • In second trimester consider: o Fasting BGL between 24–28 weeks gestation, and if BGL 4.6–5 mmol/L recommend fasting and postprandial BGL for one to two weeks68 (selfmonitoring) • In third trimester: o If evidence of excess fetal growth/adiposity is present on growth scan, repeat testing71 [refer to Table 14. Fetal surveillance] • Refer to Queensland Clinical Guidelines: Obesity in pregnancy72 • Routinely recommend an OGTT to all pregnant women, who are not known to have GDM, at 24–28 weeks gestational age7,19 • Do not perform an OGTT within one week of steroids (betamethasone/dexamethasone) administration • If receiving steroids monitor BGLs • If taking metformin for PCOS, OGTT results may be misleading • Fasting glucose test may be an alternative although this will only give partial information on glucose metabolism • Refer to Table 7. Diagnostic tests Refer to online version, destroy printed copies after use Page 16 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 3.3 Diagnosis of GDM or diabetes in pregnancy Table 9. Diabetes diagnosis Aspect Consideration • Diagnosis is based on the results of the fasting 75 g OGTT during pregnancy o One or more elevated level(s) is sufficient for a diagnosis of GDM7,19 • If fasting blood glucose test, or HbA1c (e.g. in woman who has had bariatric surgery or other reason), is an elevated value this is diagnostic of GDM7,19 • Refer to Table 10. Blood glucose level for diagnosis • Diagnosis based on glucose levels exceeding the threshold for diagnosis of diabetes6,34 [refer to Table 10. Blood glucose level for diagnosis] • If diabetes in pregnancy: o Manage woman in a centre/clinic with experience in the management of pre-existing diabetes in pregnancy1 (not suitable for a low risk model of diabetes care) o Consider screening for complications of diabetes (e.g. retinopathy and nephropathy) 1 o Higher risk of pregnancy complications1 o Consider low dose aspirin for pre-eclampsia prevention73 [refer to Queensland Clinical Guidelines Hypertension and pregnancy74 o Postpartum testing required to confirm or exclude non-gestational diabetes1 GDM Diabetes in pregnancy 3.4 Diagnostic BGL Worldwide (including Australia), HbA1c measurement and reporting has been standardised using Systeme International (SI) units. Refer to Appendix A: Conversion table for HbA1c measurement Table 10. Blood glucose level for diagnosis Diagnosis Test Test result *GDM4,7,19,21 BGL Fasting 1 hour 2 hour Plasma glucose level (one or more) • 5.1–6.9 mmol/L • Greater than or equal to 10.0 mmol/L • 8.5–11.0 mmol/L • Limited evidence suggests that HbA1c greater than or equal to 41 mmol/mol and less than 48 mmol/mol in early pregnancy sufficient to diagnose GDM75 • Lower values do not exclude GDM76,77 Plasma glucose level (one or more) HbA1c BGL Diabetes in pregnancy (DIP)4,7,19,21 Fasting 1 hour 2 hour Random HbA1c • • • • • • Greater than or equal to 7.0 mmol/L A one hour level is not used Greater than or equal to 11.1 mmol/L Greater than or equal to 11.1 mmol/L Confirm with additional standardised testing Greater than or equal to 48 mmol/mol or 6.5% in early pregnancy19,68 *Refer also to Table 7. Diagnostic tests Refer to online version, destroy printed copies after use Page 17 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 4 Antenatal care Objectives for antenatal care of women diagnosed with GDM: • Effectively manage of the diabetes • Monitor for maternal complications • Prevent fetal/neonatal complications • Provide routine antenatal care33,34,78 Refer to Table 2. Clinical standards. 4.1 Antenatal care Table 11. Antenatal care Aspect Antenatal contact Initial clinical assessment all GDM At GDM diagnosis Consideration • Individualise the antenatal schedule of contact according to clinical circumstances18,33 • If BGLs are suboptimal or there are complicating factors (e.g. hypertension, pre-eclampsia, macrosomia, intrauterine growth restriction) more frequent antenatal contact is required • GDM or DIP diagnosed before 16 weeks gestational age requires increased surveillance and monitoring, as likely to be pre-pregnancy prediabetes or diabetes37 • Refer to Appendix B: Gestational weight gain • All routine antenatal assessments are indicated throughout pregnancy • Develop an individualised plan of care with women whose pregnancy is complicated with diabetes33 o Review and update the plan at frequent intervals • Recommend ultrasound scan (USS) at 28+0–30+6 weeks gestation33 to asses fetal growth including fetal abdominal circumference (AC), and to establish a baseline for future evaluation • Order laboratory evaluation of serum creatinine • Review history—previous GDM, medications • Refer for diabetes educator and dietitian consult within one week of diagnosis • Provide psychosocial assessment and support–refer as required • Commence BGL self-monitoring • Review pre-pregnancy BMI1 and discuss individualised healthy weight gain targets in pregnancy • Discuss lifestyle factors including physical exercise and smoking cessation (if applicable) • Provide request forms for USS and laboratory investigations including serum creatinine at 28+0–30+6 weeks gestation • If pharmacological therapy commenced: o Follow-up contact within three days by health care provider o Weekly diabetes educator review • Review timing of next contact (at clinic, or by phone, telehealth or email) o Fortnightly until 36+0 weeks gestation o Weekly until birth o Increase as indicated • If obesity also present consider anaesthetist review [refer to Queensland Clinical Guidelines Obesity in pregnancy72] Refer to online version, destroy printed copies after use Page 18 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 4.2 Maternal care Table 12. Maternal care Aspect Monitoring Weight Urine testing Consideration • Women with GDM require increased surveillance throughout pregnancy o Consider other risk factors to determine model of care and frequency of antenatal contact o Maintain a high index of suspicion for associated conditions (e.g. preeclampsia) o Refer to Table 5. Maternal risks • At each antenatal contact: o Reassess if increased antenatal contact with the multidisciplinary team members is required o Review BGL self-monitoring records o Assess psychosocial needs, and offer support or referral as appropriate for the woman—consider stress related to GDM diagnosis and management o Review lifestyle factors–weight gain trends, diet, exercise, smoking cessation (if applicable) o Test urine for proteinuria o USS scan as indicated [refer to Table 14. Fetal surveillance] • Women participating in Ramadan fasting will require a practical approach and close consultation with the health care team79 o Ramadan fasting is associated with lower mean glucose levels and higher rates of hypoglycaemia than non-fasting women80 • Pre-pregnancy obesity and excessive GWG are independent risk factors for fetal macrosomia in women with GDM81 • Compared to normal weight women without GDM81 o Normal weight women with GDM are 1.94 times as likely (95%CI 1.43– 2.68) to have LGA baby o Obese women with GDM are 5.47 times as likely (95% CI 4.34–6.90) to have LGA baby • Discuss GWG in a sensitive and non-judgemental manner that minimises maternal anxiety27 o Refer to Table 5. Maternal risks • Calculate pre-pregnancy BMI at the first opportunity • Recommend and discuss desirable GWG and rate of GWG o GWG recommendations for the woman with GDM are the same as other pregnant women o Refer to Appendix C: Antenatal schedule of care o Refer to Queensland Clinical Guideline Obesity in pregnancy72 • Weigh woman at each visit o Rapid GWG may indicate polyhydramnios o Inadequate GWG or weight loss may reflect inappropriate restriction of dietary intake and/or improved diet quality • If woman not already under dietetic care, consider referral to a dietitian • Refer to Australian Dietary Guidelines72,82 • Test urine at each antenatal visit33 • Proteinuria may indicate other complications (e.g. pre-eclampsia or renal impairment or nephropathy)83 • Glycosuria is not a reliable indicator of inadequate glycaemic management84 Refer to online version, destroy printed copies after use Page 19 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 4.3 Special considerations Table 13. Special considerations Aspect Breastfeeding preparation Diabetes in pregnancy Post bariatric surgery Consideration • Advise women of benefits of breastfeeding after GDM, including prevention of newborn hypoglycaemia, childhood obesity and diabetes for women and child1 • Advise women who are considered low risk to express antenatally o Not recommended for women with a history of antepartum haemorrhage or placenta praevia, more than one previous caesarean section (CS), fetal growth restriction, documented macrosomia, polyhydramnios, hypertension, fetal compromise, or other serious maternal medical condition85 • There was no harm identified in a study (DAME trial) of advising low risk women about the benefits of routine antenatal expression of breast milk85 o There are potential benefits for the newborn baby86 o For low risk women with GDM or DIP, advise about commencing hand expression (for 10 minutes no more than twice per day) from 36+0 weeks of gestation85 o Refer to local policies and guidelines • Review and/or recommend morphology USS as there may be an increased risk of fetal congenital anomaly34 o If BGL above target levels in first trimester offer tertiary morphology USS • Test for retinopathy33 as the presence of these are associated with a substantially increased risk of developing pre-eclampsia o Recommend optometrist or ophthalmologist review6,34 • Test for microalbuminuria26as worsening nephropathy and super-imposed pre-eclampsia are most common cause of preterm birth in women with GDM26 • Consider starting pre-eclampsia prophylaxis (aspirin and/or calcium supplement) prior to 16+0 weeks gestation73 o Refer to Queensland Clinical Guidelines Hypertension and pregnancy74 • Screen for micronutrient deficiencies71 • Refer woman early in pregnancy for specialist dietary advice to optimise micronutrient supplementation, dietary intake and symptom management71 • If woman has had gastric banding surgery: o Increased risk of small for gestational age (SGA) baby [refer to Table 14. Fetal surveillance] o In first trimester, refer for management of gastric band in case of hyperemesis and to prevent nutrient deficiency71 o In second and third trimesters assess GWG and fetal growth—band may require adjusting71 o Refer to Queensland Clinical Guidelines Term small for gestational age baby87 Refer to online version, destroy printed copies after use Page 20 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 4.4 Fetal surveillance Table 14. Fetal surveillance Aspect Context Fetal growth and wellbeing Consideration • There is limited evidence or consensus regarding specific antepartum tests or their frequency, for fetal wellbeing88 • Monitoring type and frequency is influenced by the presence of other pregnancy complications (e.g. antepartum haemorrhage, pre-eclampsia, fetal growth restriction) as well as severity of maternal hyperglycaemia89 • Fetal AC on USS greater than or equal to 75th percentile for gestational age, measured at 29+0 to 33+6 weeks gestation, correlates with evidence of excess fetal growth/adiposity and an increased risk for birth of an LGA baby90 o May require more intensive glucose lowering therapy90 o If fetal USS shows normal growth is maintained, consider relaxing glycaemic targets90 • Perform clinical assessment of fetal size and amniotic fluid volume12,91 • Assess the fetal response to maternal GDM by USS measurement of fetal AC commencing at 28+0–30+6 weeks gestation12,92 • Longitudinal growth assessment is superior to a single measurement late in pregnancy if abnormal on first scan • Accelerating AC especially if greater than 95th percentile is clinically significant • Consider 2–4 weekly USS for women with unstable diabetes or who require pharmacological therapy or comorbid risk factors (e.g. obesity, hypertension, LGA or SGA , previous stillbirth)12 o If fetal growth restriction is suspected, follow usual imaging fetal surveillance including umbilical artery and middle cerebral artery Doppler12 • If excessive fetal growth or AC above 75th centile is detected, consider more intensive management90,93 which may include: o Lower blood glucose targets for glycaemic management o Addition of pharmacologic therapy o Altered frequency of scans and interpretation • Obstetric USS may be suboptimal in women with GDM and/or postbariatric surgery o May affect accuracy of estimated fetal weight (EFW) § EFW generally within 10% of actual birthweight o Remains clinically reliable to identify LGA and SGA Refer to online version, destroy printed copies after use Page 21 of 46 Queensland Clinical Guideline: Gestational diabetes mellitus (GDM) 4.5 Psychosocial support and education Table 15. Psychosocial support and education Aspect Context Information and education Psychosocial support Consideration • Emotional well-being is an important part of diabetes care and selfmanagement94 • Rapport between the woman and the health care provider can enhance compliance95 • Barriers to effective treatment response in women with GDM include depression, eating disorders, stress and anxiety96 • Individualise the approach to management and consider95 o Cultural/language background o Learning ability and style of learning (e.g. written information, visual) o Family and social circumstances • Provide women and their families comprehensive information about GDM to aid in self-management including34: o Implications of GDM for the woman and her baby (short and long-term) o Dietary and physical activity recommendations [refer to Table 18. Physical activity] o Self-monitoring of blood glucose procedures and targets o Advice about seeking urgent medical advice if they become hyperglycaemic or unwell o Importance of long term follow-up • Provide information about NDSS website for additional resources • Discuss risk of newborn hypoglycaemia, and need for BGL monitoring and management of baby after birth for at least the first 24 hours o Provide Queensland Clinical Guideline parent information Newborn hypoglycaemia97 • Support women to make positive