Shantha JosephEndocrinologist

Obstetric physicianSothern Adelaide Local Health Network

Gestational diabetesGP Obstetric Shared Care Program

Accreditation Seminars

Objectives •O

verview of gestational diabetes

•Diagnostic criteria

•Recommendations for management

•Case discussions

•GDM glucose intolerance of variable severity with onset or first recognition during pregnancy.

•The diagnosis of GDM includes those women with previously undiagnosed abnormalities of glucose tolerance, as well as women with glucose abnormalities related to the pregnancy alone.

• A definitive diagnosis of non‐gestational diabetes cannot be made until the post partum period

Gestational Diabetes Mellitus (GDM)

•Most frequent metabolic complication of pregnancy

•Gestational diabetes is generally defined as diabetes with initial onset or recognition during pregnancy

•Accounts for 90% of diabetes in pregnancy

• Affects ~7% of all pregnancies (range 1-14%) Highest in ethnic groups with high frequencies of type 2 diabetes (Aboriginal, Asian, and Pacific Island ancestry)

•independent of changes in definition,the prevalence of gestational diabetes is increasing

Changes in maternal glucose and insulin sensitivity in pregnancy

•Pregnancy results in profound changes in maternal metabolism

•During normal pregnancy there is a major change in insulin sensitivity

•marked fall in insulin sensitivity late in pregnancy, seen by all investigators

•50–70% reduction in insulin sensitivity in women with gestational diabetes compared with controls

•In response to the insulin resistance,insulin secretion is increased and the net change in glucose for the majority of women increase is relatively small,

•Plasma glucose declines with pregnancy• may reflect both dilutional effects and increased use by the foeto-placental unit

•the main biological difference between women with gestational diabetes and others is a failure of insulin secretion to rise in response to the physiological insulin resistance of pregnancy• ? Underlying genetic factors

• Environmental co-factors

• failure of beta cell to produce increased insulin in response to the increased resistance- various causes

Consequences of GDMMaternal Morbidity

•Hypertension

•Preeclampsia

•Increased likelihood of C-section

•Development of diabetes after pregnancy

Fetal Morbidity •M

acrosomia (excessive birth weight) •N

eonatal hypoglycemia •P

olycythemia •I

ncreased perinatal mortality •C

ongenital malformation •H

yperbilirubinemia •R

espiratory distress syndrome •H

ypocalcemia

Diagnostic criteria and recommendations for management

REVIEW OF LITERATURE

Objective: to clarify the risks of adverse outcomes associated with various degrees of maternal glucose intolerance less severe than that in overt diabetes mellitus

23,316 pregnant women without overt diabetes 15 centers in 9 countries over 6 years (July 2000 – April 2006)

Protocol Limitations

•No universal protocol

•Impossible to compare different studies of GDM

•? true prevalence of GDM

•? risks associated with maternal hyperglycemia

•Consensus Needed for New Criteria

•International Association of Diabetes in Pregnancy Study Groups (IADPSG)

•2008 conference to review HAPO and related studies data

•Establish new diagnostic criteria for GDM

SAPPG

• OGTT May be performed at any time during pregnancy if symptoms and signs of abnormal glucose tolerance e.g. excess thirst; polyuria, polyhydramnios, macrosomia

•Consider an early test (around 12-16 weeks of gestation) for women with a past history of gestational diabetes if a recent OGTT has not been performed

•Women with known glucose intolerance outside pregnancy may be considered to have gestational diabetes from the time of conception and therefore a repeat OGTT is not required

•Universal screening at 26-28 weeks GA – OGCT

•If positive proceed to OGTT

ADIPS 2002•H

igh risk factors:

• Glycosuria;

• Age over 30 years;

• Obesity;

• Family history of diabetes;

• Past history of GDM or glucose intolerance;

• Previous adverse pregnancy outcome; and

• Belonging to an ethnic group with a high risk for GDM

ADIPS 2013•R

ecommendations for early testing for GDM for women with high risk• Previous GDM• Previously elevated blood glucose level• Ethnicity: Asian, Indian, Aboriginal, Torres Strait Islander, Pacific Islander, Maori, Middle Eastern, non‐white African• Maternal age ≥40 years• Family history DM (1st degree relative with diabetes or a sister with GDM)• Obesity, especially if BMI > 35 kg/m2• Previous macrosomia (baby with birth weight > 4500 g or > 90th centile)• Polycystic ovarian syndrome• Medications: corticosteroids, antipsychotics

ADIPS 2013All women not known to have GDM, should have a 75g OGTT at 24–28 weeks gestation

•A diagnosis of GDM is made if one or more of the following glucose levels are elevated;

• Fasting glucose ≥ 5.1mmol/L

• 1‐hr glucose ≥ 10.0mmol/L

• 2‐hr glucose ≥ 8.5mmol/L

How does this compare with the existing protocol Current protocol based on ADIPS 2002

New ADIPS recommendations- not accepted yet

Universal screening at 26-28 weeks with GCT- 50 gm glucose- ≥ 7.8 mmol/LIf positive – 75gm OGTT

High risk – 75 gm OGTT at time of contact with health systemAll others OGTT at 24-28 weeks

OGTT Diagnostic criteria•Fasting glucose ≥ 5.5mmol/L•2‐hr glucose ≥ 7.8 mmol/L (SAPPG- 8.0 mmol/l)

OGTT Diagnostic criteria•Fasting glucose ≥ 5.1mmol/L•2‐hr glucose ≥ 8.5mmol/L

Therapeutic criteria•fasting glucose level <5.5 mmol/L• 2 hour glucose level <7.0 mmol/L

• Fasting glucose ≤ 5.0mmol/L• 2 hour glucose ≤ 6.7mmol/L

CURRENT PRACTICE IN SA

Diagnostic criteria for Gestational DiabetesSAPPG-Based on ADIPS criteria- 2002Universal screening plus high risk patients screened earlier •The recommended screening test for GDM- OGCT• performed at 26-28 weeks' gestation and positive results are:• 1 hour venous plasma glucose level 7.8 mmol/L after a 50 g glucose load (morning, non-fasting);

•Confirmation of diagnosis after a positive screening test:OGTT• a 75 g oral glucose tolerance test (fasting) with a venous plasma glucose level at •0 hours of 5.5 mmol/L and/or at• 2 hours of 8.0 mmol/L.

Post diagnosis•R

eview by Diabetes nurse educator –• group session with DNE and dietician

• BGL monitoring, provision of glucometer and forms for NDSS-for supplies

•BGL monitoring- 4 times a day• Fasting, 2 hours after BF, lunch and dinner

• Targets- fasting <5.5 mmol/L and post meal<7 mmol/L

•Review in Obs med clinic- usually 1-2 visits unless issues present

•Phone contact with DNE

Imaging studies

•Ultrasound for fetal size at least once at 36 to 37 wk; more frequently if macrosomia suspected

•Fetal echo if required

Antenatal testing

•Routine blood pressure and urine protein monitoring

Non-pharm Rx

•Regular moderate exercise

•Dietary modifications aimed at glycemic control:

• low-fat, high-fiber diet; avoid sugar and concentrated sweets; and eat small, frequent meals.

• Nutrition counseling for diet that adequately meets the needs of pregnancy but restricts carbohydrates to 35% to 40% of daily calories.

• For women with a body mass index >30, restrict calories to 25 kcal/kg actual weight per day.

Pharmacologic Rx •S

tart if BSLs > cutoff on at least 2 occasions during same time period of the day

•Clinical judgement

• re-educate – DNE review

•If fasting values are elevated, use NPH at bedtime

•If postprandial values are elevated, use ultra rapid-acting insulin before meals

•Metformin in select patients

Post-partum•G

lucose profile on day 3-4 post partum

•All women with gestational diabetes should have a glucose tolerance test at 6-12 weeks post partum

•The Gestational Diabetes Recall Register should be offered (if the woman has not already been recruited to this) to facilitate long-term follow-up

CASES

•Ms BY

•28 year old recently migrated from Canada

•BMI-24

•Non smoker, nil medical issues

•Maternal grandmother had late onset T2DM

•When to test?

•Issues of concern

•Best place of care• Pros and cons

Ongoing nausea- unable to tolerate GCT

Alternative diagnostic tests include capillary blood glucose monitoring (fasting and postprandial over a week and review

Alternative Approaches

• Jelly beans for GDM screening (AJOG 1999;181:1154–1157)

50 g glucose beverage is intensely sweet 15-20% of patients experience nausea and vomiting (voids test)

• 28 Brach’s No. 110 jelly beans = 50 g glucose

• Poor sensitivity compared to beverage (40 vs. 80%, respectively)

•HAPO• Hb A1c-not a useful alternative to OGTT

•ADIPS 2013-

•measurement of HbA1c - level of ≥ 48mmol/mol (6.5%) is diagnostic of GDM and very likely represents previous undiagnosed type 2 diabetes

•Can be considered-• In areas where the rate of undiagnosed type 2 diabetes is thought to be

high,

• In remote areas where the performance of a GTT may be logistically difficult,

•Ms AZ 42 year old primi,

•Caucasian

•History of PCOS

•Obese, non-smoker

•Family history of DM- brother and father- T2DM

•When to test?

•Issues of concern

•Best place of care• Pros and cons

GCT- 8.5 mmol/LOGTT-F-5.9 mmol/L2h PP- 9.1 mmol/L

BSL monitoringRaised BSL in fasting column >2 x in a fortnight

Needle phobic- teary 16 weeks GA- options

Ongoing hyperglycemia- Rx options

Metformin

•Metformin versus Insulin for the Treatment of Gestational Diabetes MiG Trial NEJM 2008

• showed that use of metformin gives comparable outcomes to insulin in the management of women with gestational diabetes.

•Women treated with metformin had offspring with less severe neonatal hypoglycaemia.

•They gained less weight during pregnancy and lost more weight after delivery.

•Women preferred treatment with metformin.

•Follow up of the offspring to date has shown no difference between those whose mothers were treated with insulin and those whose mothers were treated with metformin

Summary •G

DM glucose intolerance of variable severity with onset or first recognition during pregnancy.

•Important to recognise as maternal and fetal consequences can be dangerous

•SAPPG in line with ADIPS 2002- no change to criteria for diagnosis or management till further research- which is being planned

•Alternative approaches for diagnosis- • BSL monitoring x 1 week• HbA1C

•Alternative approaches for Rx• Metformin vs insulin

•Post partum- critical to do OGTT

THANK YOU