Trust Guidelines for the Diagnosis and Management of Gestational Diabetes Mellitus (GDM)

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1 A Clinical Guideline recommended for use In: Maternity By: For: Division responsible for document: Key words: Name of document author: Job title of document author: Name of document author s Line Manager: Job title of document author s Line Manager: Supported by: Assessed and approved by: Obstetricians, Endocrinologists Pregnant women with identified risk of developing GDM Divisions 2 and 3 (Endocrinology and Obstetrics) Gestational diabetes mellitus, GDM, diagnosis, pregnancy Alastair McKelvey / Fran Harlow Consultant Obstetricians Frances Bolger Date of approval: 24/08/2018 Ratified by or reported as approved to: To be reviewed before: This document remains current after this date but will be under review To be reviewed by: Chief of Women s and Children s Services Jeremy Turner, Consultant Diabetes and Endocrinology, Sue Land, Diabetes Specialist Midwife Obstetrics and Gynaecology 2802 Maternity Guideline Committee approved chair s action Clinical Standards Group and Effectiveness Sub- Board 24/08/2021 Alastair McKelvey / Fran Harlow Reference and/or Trustdocs ID No: AO6 ID No: 844 Version No: 6 Description of changes for revised versions Compliance links: (is there any NICE related to guidance) If Yes does the strategy/policy deviate from the recommendations of NICE? If so, why? Significant changes to fall in line with the diabetes in pregnancy guideline, and change to is offered glucose tolerance tests to Diabetes in pregnancy. Management of diabetes and its complications from preconception to the post-natal period). (CG63).(2015) No This guideline has been approved by the Maternity Guidelines Committee as an aid to the diagnosis and management of relevant patients and clinical circumstances. Not every patient or situation fits neatly into a standard guideline scenario and the guideline must be interpreted and applied in practice in the light of prevailing clinical circumstances, the diagnostic and treatment options available and the professional judgement, knowledge and expertise of relevant clinicians. It is advised that the rationale for any departure from relevant guidance should be documented in the patient's case notes. The Trust's guidelines are made publicly available as part of the collective endeavour to continuously improve the quality of healthcare through sharing medical experience and knowledge. The Trust accepts no responsibility for any misunderstanding or misapplication of this document. Trust Guideline for: Diagnosis and Author/s: Alistair McKelvey/Fran Harlow Author/s title: Consultant Obstetrician Approved by: MGG Date approved: 25/08/2018 Review date: 25/08/2021 Available via Trust Docs Version: 6 Trust Docs ID: 844 Page 1 of 11

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3 Objective/s: To provide guidance on identification and management of women with Gestational Diabetes Mellitus (gdm). Rationale: The potential benefits of recognising and treating gestational diabetes include reductions in ill health in the woman and/or the baby during or immediately after pregnancy, as well as the benefits of reducing the risk of progression to type 2diabetes in the longer term. (NICE 2015) Most women with gestational diabetes will be asymptomatic so risk factor screening is advised. Although this guideline is written to provide guidance for the identification, testing and subsequent management of a positive Pregnancy Oral Glucose Tolerance Test (POGTT), it should be used in conjunction with the Trust guideline The Management of Diabetes Mellitus in Pregnancy ID 839 Definition: Gestational diabetes mellitus (GDM) is defined as glucose intolerance with onset or first recognition during pregnancy. The definition applies whether insulin, oral hypoglycaemic (metformin) or diet modification is used for treatment and whether or not the condition persists after pregnancy. (ADA 2003) Pathophysiology of GDM: During early pregnancy, increases in oestrogens, progesterone, and other pregnancyrelated hormones lead to lower glucose levels, promotion of fat deposition, delayed gastric emptying, and increased appetite. As gestation progresses, postprandial glucose levels steadily increase as insulin sensitivity steadily decreases. For glucose control to be maintained in pregnancy, it is necessary for maternal insulin secretion to increase sufficiently to counteract the fall in insulin sensitivity. GDM occurs when there is insufficient insulin secretion to counteract the pregnancy-related decrease in insulin sensitivity. (2) Introduction: More than three quarters of pregnancies complicated by diabetes are estimated to be due to gestational diabetes. (NICE 2015) The prevalence of gestational diabetes in Europe is between 12 to 15 % of all pregnancies. Using current criteria, local data shows an prevalence of around 12% of completed pregnancies Maternal hyperglycaemia results in excessive transfer of glucose to the fetus, resulting in fetal hyperinsulinaemia, leading to an overgrowth of adipose tissue (especially round the neck, shoulders and abdomen), a hypoxaemic state in utero, which may lead to IUFD, Trust Guideline for: Diagnosis and Author/s: Alistair McKelvey/Fran Harlow Author/s title: Consultant Obstetrician Approved by: MGG Date approved: 25/08/2018 Review date: 25/08/2021 Available via Trust Docs Version: 6 Trust Docs ID: 844 Page 3 of 11

4 neonatal hypoglycaemia and an increased long term risk of obesity and diabetes in the child (NICE 2015) For the mother, there is an increased risk of induction of labour, trauma during the birth (macrosomic baby), Caesarean Section and of developing Type 2 diabetes in later life (NICE 2015). Risk factors for GDM and timing of pregnancy oral glucose tolerance test (POGTT) Although the effects of gestational diabetes on the pregnancy itself are recognised, there is less clarity concerning screening. In the absence of clear evidence supporting universal screening for GDM, the screening in NNUH is by risk factors. Risk Factors From history During pregnancy Previous baby > 4.5 kg Previous unexplained IUFD Previous unexplained hypoglycaemic baby Maternal obesity: BMI > 30 Parents or siblings with a history of diabetes Ethnic origin with high prevalence of diabetes Previous GDM in pregnancy Recent or current medication of atypical antipsychotics: Aripiprazole Olanzapine Quetiapine Risperidone Ziprasidone Glycosuria once before 20 weeks For other third trimester indications for POGTT before 36 weeks, see flow chart on p5 After 36 weeks Timing of POGTT, POGTT at booking Repeat at weeks if normal POGTT at time of diagnosis Maximum of 3 POGTTs during pregnancy, according to flow chart Do not do POGTT unless clinical suspicion of overt diabetes (see paragraph below) Glycosuria in the first trimester is probably not caused by recent ingestion of sugar. Pregnancy lowers the renal threshold for glucose excretion and glycosuria results, but it is uncommon before 20 weeks Management of a woman symptomatic of diabetes: As overt diabetes can occur at any time, if the patient is symptomatic of diabetes, urgently perform either a fasting venous plasma glucose (FPG) or random venous plasma glucose (RPG).

5 If the FPG is greater than, or equal to, 7.1 mmol/l, or the RPG is greater than, or equal to 11.1mmol/L, refer urgently to either the Diabetes Specialist Midwife (bleep 0849) or Antenatal Clinic ( ) Out of hours help may be sought from a Consultant Endocrinolgist but it is expected that contact is made by the Obstetric SpR or above. Performance of a Pregnancy Oral Glucose Tolerance Test (POGTT): If the patient is identified as having risk factors for GDM, perform a POGTT. This is usually performed at weeks but may be performed at other times if clinically indicated. The POGTT can be performed in the hospital or the GP surgery, and must be performed in the morning. The patient should have at least 3 days of unrestricted diet and must fast for between 8 and 14 hours (usually from midnight) with only water to drink. She must also be advised not to smoke or to chew gum. A fasting BM is taken before the formal OGTT. If 10 mmol/l proceed with OGTT. If >10, refer to the Diabetes Specialist Midwife (DSM), who will start BM monitoring and do not perform OGTT. For a formal OGTT Fasting venous plasma glucose is taken Either Polycal 113mls or 75g glucose in 250mls water must be drunk within 10 minutes 2 hours later venous plasma glucose must be obtained. The woman is then free to eat and drink normally Diagnostic criteria for Gestational Diabetes The NNUH has moved to use NICE 2015 criteria for diagnosing GDM: One or both of the results must be equal to, or above the thresholds stated below in order to make a diagnosis of GDM: Polycal/75-g glucose mmol/l Fasting hours 7.8 Action if the GTT is Abnormal: All abnormal results are ed directly to a Diabetes Specialist Midwife (DSM) mailbox so will be accessed and actioned by either the DSM or ANC midwives. If any advice is required re a POGTT result, then call the Diabetes Specialist Midwife (Bleep 0849) or Antenatal Clinic ( ). POGTTs performed between 32 and 36 weeks gestation will be acted upon only after discussion between one of the diabetic specialist midwives and one of the Diabetes

6 Consultants. The indications for a repeat third trimester POGTT are in the following flow chart (it is expected women will not have more than 3 POGTTs during pregnancy):

7 1 st Antenatal visit with Diabetes Specialist Midwife (DSM) /Diabetes Specialist Dietician: The woman will Receive information on the principles of the pathophysiology of GDM, including the increased risk of development of Type 2 diabetes mellitus in later life Be advised re the importance of the 6 week postnatal glycaemic check and annual screening Be advised re the importance of a healthy lifestyle (weight loss, diet, exercise) to reduce the chance of developing Type 2 Diabetes Be taught home blood glucose monitoring (HBGM) (using Optium, One Touch or Expert meters) and advised to test fasting and post prandial glucose levels (initially) Receive dietary advice, including a dietary leaflet (as part of the GDM patient leaflet), regarding a low carbohydrate/low GI diet Keep a food diary until the joint clinic appointment (1 week later) Be encouraged to increase physical activity, such as walking. Have an HbA1c measured Women need to be told to bring the blood glucose meter/record book to every antenatal appointment GDM women will generally be seen in the Wednesday Diabetes Antenatal Clinic now it is appropriately staffed. Follow up Visit to MDT clinic If the woman is over 26 weeks gestation, and there has been 2 weeks or more since the last scan, perform an ultrasound scan for growth, liquor volume and dopplers. The following is a guideline as to whether to start hypoglycaemic agents (insulin and/or metformin) if the woman is adhering to dietary advice 1. The fasting plasma glucose is consistently above 5.3 mmol/l for more than three days 1. Post prandial blood glucose measurements repeatedly above 7.8 mmol/ for more than 3 days Target for blood glucose control Women with GDM on diet alone, metformin and/or once daily insulin are asked to do a fasting and three postprandial glucose tests. Women with GDM on 3 daily insulin injections are requested to do a minimum of 7 preprandial and postprandial capillary glucose measurements daily (fasting, pre meal, 1 hour after the beginning of the meal and at bed time, unless otherwise discussed), and

8 occasional night testing. Measurements should be made using a meter with the ability to download data and recorded in a home diary. Targets for blood glucose control should be individualised but are likely to be: Fasting blood glucose < 5.3 mmol/l Preprandial mmol/l 1 hour postprandial < 7.8 mmol/l Women on insulin must be aware to self-refer if they have decreasing insulin requirements/hypoglycaemia later in pregnancy as it may indicate concern about placental function. They should test their blood glucose prior to driving and keep carbohydrate in the car at all times. Antenatal Appointments Antenatal appointments include an ultrasound scan at 28, 32 and 36 weeks (fetal growth, liquor volume and dopplers) and blood glucose review will be at the discretion of the diabetes team. GDMs progressing beyond 38 weeks should have an additional USS at 38 and 39 weeks. Fetal size may be underestimated at extremes of birth weight/maternal habitus. If delivery is planned at 38 weeks, a scan is not usually indicated at this time. Women should be advised to continue to see their Community Midwife. Phone review of blood glucose in between may be arranged. Birth preparation will be offered around 34 weeks of pregnancy. This will include information regarding The process of Induction of Labour Birth plan discussion Positions for labour Pain relief for labour Spontaneous onset/signs/contact numbers Continuous fetal monitoring Hourly blood glucose testing Variable rate intravenous insulin infusion (VRIII) /rationale Separate IV access if augmentation required LSCS/forceps/ventouse/episiotomy Antenatal hand expressing/colostrum harvesting (if breastfeeding) Principles of positioning for breastfeeding (if breast feeding) Benefits of skin to skin contact Early feed (within first hour) Blood glucose monitoring for the baby

9 Neonatal hypoglycaemia and supplementary feeding Steroid administration: This involves admission to hospital for intravenous insulin infusion and very frequent blood sugar testing. Therefore the decision to give steroids should not be taken lightly. If the clinical picture suggests the woman may benefit from antenatal steroids, this must be discussed with the named Obstetrician. If this is not possible, then discussion should occur with the on call Consultant Obstetrician. Refer to the guideline The Management of Diabetes Mellitus in Pregnancy ID 839 for glycaemic control/intravenous insulin infusion during this period. If Elective Caesarean Section is planned, routine steroid administration should be avoided after 37 weeks. Review of unexpected term admissions to the neonatal unit takes place within the hospital and this will include TTN. Labour/delivery: Use the guideline The Management of Diabetes Mellitus in Pregnancy ID 839. For women with uncomplicated GDM without maternal or fetal complications ie normal size baby with normal liquor volume and optimal glucose control (7- day average glucose 6mmol/L), delivery should be offered by week. For women with GDM with suboptimal glucose control (7-day average glucose > 6.0 mmol/l) and/or with maternal or fetal complications, delivery should be considered from 38 weeks. Discuss with consultant diabetologist and obstetrician. Hourly blood glucose monitoring from ARM/3cm and if two blood glucose reading is >7mmol/L, start an Intravenous Insulin Infusion (scale dependant on antenatal glycaemic treatment see guideline The Management of Diabetes Mellitus in Pregnancy ID 839 to reduce the chance of neonatal hypoglycaemia Postnatal management: Mother a) Insulin infusion if required: stop (along with metformin) b) Blood glucose monitoring until first meal: continue 4 hourly c) Subsequent Blood glucose monitoring: 3 pre-meal glucose measurements. If <10mmol/L stop testing. If >10mmol/L refer to diabetes team and do not restart insulin without their instruction. d) Women diagnosed in early pregnancy may have different requirements so check special instruction in post natal pages) e) The woman will be seen prior to discharge to re discuss the increased risk of developing Type 2 diabetes, 6 week glycaemic check (fasting blood glucose), annual screening (HbA1c) f) Diet: encourage healthy diet choices with low GI Diet. g) Weight: encourage weight loss if BMI >30 or to avoid weight gain if normal BMI. h) Exercise: encourage change in lifestyle if sedentary prior to pregnancy. Walking can be promoted as beneficial.

10 Postnatal management: Baby a) Avoid separation of mother and baby by unnecessary admission to NICU. b) Women should be encouraged to breast feed. Sleeping with the baby in bed is actively discouraged (see guideline No co-sleeping policy for babies up until the age of 6 months whilst in hospital MIDCS) c) The baby will need a feed within the first hour. The baby must be monitored as per guideline Management of neonatal hypoglycaemia (CA2036) Follow up: ALL women with GDM need a fasting glucose 6 weeks postnatally, to establish post pregnancy glycaemia (unless continuing on medication post delivery). Occasionally, a post natal OGTT may have been requested but this will have been discussed with the woman by the MDT. The DSM will write to the woman, regardless of whether there is a test result or not. If there is no result, she will be advised to contact her GP to have this done. The DSM will discuss: An increased risk of developing Type 2 diabetes. Annual fasting glucose with the GP The importance of a healthy lifestyle (diet, healthy weight management and exercise) To reduce the chance of Type 2 diabetes Early POGTT in future pregnancies Clinical audit standards: The Maternity Services are committed to the philosophy of clinical audit, as part of its Clinical Governance programme. The standards contained in this clinical guideline will be subject to continuous audit, with multidisciplinary review of the audit results at one of the monthly departmental Clinic Governance meetings. The results will also be summarised and a list of recommendations formed into an action plan, with a commitment to re-audit within three years, resources permitting. Summary of development and consultation process undertaken before registration and dissemination The authors listed above drafted this guideline on behalf of Obstetric and Endocrinology teams who have agreed the final content. During its development it was has been circulated for comment to: Antenatal Diabetes clinic team. It was reviewed in August 2018 to match to fall in line with the diabetes in pregnancy guideline, and change to is offered glucose tolerance tests to This version has been endorsed by the Maternity Guidelines Committee

11 Distribution list/ dissemination method To Obstetricians and midwifery teams. Intranet and copies to Community Midwife CMWs. Trustdocs References/ source documents Alwan N, Tuffnell DJ, West J. Treatments for gestational diabetes. Cochrane Database of Systematic Reviews 2009;(3):CD Metzger BE, Lowe LP, et al. Hyperglycaemia and adverse pregnancy outcomes (HAPO). N Engl J Med. 2008; 358: National Institute for Health and Care Excellence (2015) (Diabetes in pregnancy. Management of diabetes and its complications from preconception to the post natal period). (CG63). London: National Institute for Health and Care Excellence.