this is an update on GDM management from ADA and NICE guidelines

1. Dr Namkha Dorji
Resident (Phase B)
Department of Obstetrics and gynaecology
Bangabandhu Sheikh Mujib Medical University

2. Criteria for Diabetes Diagnosis: 4 options
1. A1C ≥6.5%
2. FPG ≥126 mg/dL (7.0 mmol/L)
3. 2-hr PG ≥200 mg/dL (11.1 mmol/L) during OGTT (75-g)
4. Random PG ≥200 mg/dL (11.1 mmol/L)

3. A1C <7.0%
Lowering A1C below or around 7.0% has been shown to
reduce:
Microvascular complications
Macrovascular disease
Preprandial capillary PG 80-130 mg/dL (4.1-7.2 mmol/L)
Peak postprandial capillary PG
<180 mg/dL (<10.0 mmol/L)

4. Individualize targets based on:
 Age/life expectancy
 Comorbid conditions
 Diabetes duration
 Hypoglycemia status
 Individual patient considerations

5. “One-Step” Strategy
75-g OGTT with PG measurement of fasting, at 1 h and 2 h
at 24-28 wks in women not previously diagnosed with overt
diabetes
GDM diagnosis made if PG values meet or
exceed:
 Fasting: 92 mg/dL (5.1 mmol/L)
 1 h: 180 mg/dL (10.0 mmol/L)
 2 h: 153 mg/dL (8.5 mmol/L)

6. “Two-Step” Strategy
50-g GLT (nonfasting) with PG measurement at 1 h
(Step 1) at 24-28 wks in women not previously
diagnosed with overt diabetes
If PG at 1 h after load is ≥140 mg/dL (7.8mmol/L),
proceed to 100-g OGTT (Step 2), performed while
patient is fasting
GDM diagnosis made when two or more PG levels
meet or exceed:
 Fasting: 95 mg/dL or 105 mg/dL (5.3/5.8)
 1 hr: 180 mg/dL or 190 mg/dL (10.0/10.6)
 2 hr: 155 mg/dL or 165 mg/dL (8.6/9.2)
 3 hr: 140 mg/dL or 145 mg/dL (7.8/8.0

7.  Preprandial: ≤95 mg/dL (5.3 mmol/L) and either
 1-hr postmeal: ≤140 mg/dL (7.8 mmol/L)
 2-hr postmeal: ≤120 mg/dL (6.7 mmol/)

8.  Premeal, bedtime, overnight glucose: 60-99 mg/dL (3.3-5.4
mmol/L)
 Peak postprandial glucose: 100-129 mg/dL (5.4-7.1
mmol/L)
 A1C: <6.0% (alteration in blood cell turnover that lower the
normal A1C level in pregnancy)

9.  A1C - 7% prior to conception to minimize risk
 Uncontrolled diabetes: fetal anomalies, preeclampsia,
macrosomia, intrauterine fetal demise, neonatal
hypoglycemia, and neonatal hyperbilirubinemia, among
others. In addition, diabetes in pregnancy increases the risk
of obesity and type 2 diabetes in offspring later in life.
 Fetal anomalies: anencephaly, microcephaly, and
congenital heart disease, that increases directly with
elevations in A1C

10.  Potentially teratogenic medications (ACE inhibitors, statins,
etc.) : avoided.
 GDM should be managed first with diet and exercise, and
medications should be added if needed
 Women with pregestational diabetes - baseline
ophthalmology exam in the T1 and then be monitored every
trimester as indicated by degree of retinopathy

11.  Women with type 1 diabetes have an increased risk of
hypoglycemia in the first trimester. Frequent hypoglycemia
can be associated with intrauterine growth restriction. In
addition, rapid implementation of tight glycemic control in the
setting of retinopathy is associated with worsening of
retinopathy.
 Insulin resistance drops rapidly with delivery of the placenta,
and women become very insulin sensitive, requiring much
less insulin than in the prepartum period.

12. Pregestational type 2 diabetes is often associated with
obesity. Recommended weight gain during pregnancy for
overweight women is 15–25 lb and for obese women is 10–
20 lb. Glycemic control is often easier to achieve in type 2
diabetes than in type1 diabetes, but hypertension and other
comorbidities often render pregestational type 2 diabetes as
high or higher risk than pregestational type 1 diabetes.

13.  Medical nutrition therapy (MNT) is central to the control of
GDM, and most women are adequately treated with diet
alone.
 All women should be referred to a registered dietician, if
available.
 Expert opinion suggests that women should be advised to
try to choose carbohydrates from low-glycaemic-index
sources and lean proteins.
 Diet should contain a balance of polyunsaturated and
monounsaturated fats. Saturated fats should be limited.

14.  Caloric needs are determined by pre-pregnancy ideal body
weight according to expert opinion: 30 kcal/kg for those
with normal weight and 35 kcal/kg for underweight patients.
 Reducing carbohydrates to 40% to 45% of total daily
calories reduces post-prandial hyperglycaemia;

15.  Moderate-intensity exercise (e.g., brisk walking, easy jogging,
or swimming) during pregnancy has been associated with
lowering of maternal glucose levels in some but not all
studies. (recommended by NICE and ADA).

16.  A study of women with GDM treated with dietary therapy for 4
weeks before initiating insulin found that most women who
achieved good control with diet did so within 2 weeks and had
baseline fasting plasma glucose levels of <5.3 mmol/L (<95
mg/dL). Accordingly, the authors have reasonably recommended
that patients with a fasting plasma glucose <5.3 mmol/L (<95
mg/dL) attempt dietary therapy for at least 2 weeks before starting
insulin, whereas insulin should be started at diagnosis or within a
week of failed dietary therapy in patients with fasting glucose
levels >5.3 mmol/L (>95 mg/dL). Such severe elevations imply
overt diabetes, probably occurring before pregnancy, and the need
for aggressive therapy with prompt initiation of insulin.

17.  According to NICE, hypoglycaemic therapy such as insulin
should be considered if blood glucose targets are not
maintained 1 to 2 weeks after introducing changes to diet
and initiating exercise.
 Pharmacological therapy should also be considered at the
time of diagnosis of GDM if fetal macrosomia is suspected
by ultrasound investigations

18.  The American Congress of Obstetricians and
Gynecologists (ACOG) recommends these guidelines for
insulin initiation: when fasting plasma glucose is >5.3
mmol/L (>95 mg/dL), 1-hour post-prandial plasma glucose
is >7.2 to 7.8 mmol/L (>130 to 140 mg/dL), or 2-hour post-
prandial plasma glucose is >6.7 mmol/L (>120 mg/dL).

19.  Insulin needs are highly variable. Requirements increase
throughout pregnancy and average 0.8 units/kg/day in the
first trimester, 1.0 unit/kg/day in the second trimester, and 1.2
units/kg/day in the third trimester.
 Insulin therapy requires highly individualised titration. For
isolated fasting hyperglycaemia, a useful approach is to start
10 units of NPH (Neutral Protamine Hagedorn) long-acting
insulin at bedtime and then adjust the dose to achieve fasting
blood sugar <5.3 mmol/L (<96 mg/dL).

20.  To address post-prandial hyperglycaemia, one approach is to
use long-acting insulin once or twice daily, with short-acting
prandial insulin (e.g., lispro, aspart) titrated to meet glycaemic
targets.
 Insulin is titrated with the goal of normalising blood sugar.
Target glucose levels are below the criteria for insulin
initiation (see ACOG and ADA criteria above).

21.  FM monitoring for women with GDM beginning at 32 to 34
weeks’ gestation is recommended: sufficient in women with
good glycaemic control with only dietary therapy, but
randomised trials are lacking.
 For women with poor GDM control and those requiring
insulin therapy, more intensive fetal monitoring with non-
stress tests, contraction stress tests, or biophysical profile
assessments is worth considering as per recommendations
from ACOG and the Fifth International Workshop-
Conference on Gestational Diabetes Mellitus

22.  USG is recommended to assess for congenital fetal
anomalies in women with GDM presenting with an HbA1c
≥53 mmol/mol (≥7%) or a FPG >6.7 mmol/L (>120 mg/dL).
 If ultrasound estimates are used, an abdominal
circumference >75th percentile should prompt
consideration of initiating or intensifying insulin therapy to
lower the risk of large for gestational age offspring.
 Ultrasonography is also used to assess fetal size and may
have utility in planning route of delivery. Although
ultrasound estimates of fetal weight have limitations,
particularly in women with a high BMI, ultrasound is a non-
invasive tool that can provide additional data to guide
delivery planning.

23.  As increasing fetal size - increased risk of shoulder
dystocia and birth trauma - assessment of fetal size
(clinically/ultrasound), may be useful in planning delivery
route.
 Fetal macrosomia is not itself an indication for delivery;
however, c/s may be offered to women with an EFW of
>4500 g.
 Intrapartum glycaemic monitoring is particularly advisable
in women with GDM requiring insulin.
 controlling maternal plasma glucose levels to <6.1 mmol/L
(<110 mg/dL) during labour is recommended.

24.  When labour is planned or already initiated in women with
insulin-treated GDM, long-acting insulin is held and plasma
glucose of <6.1 mmol/L (<110 mg/dL) is maintained by
infusing insulin and glucose if needed. If insulin has already
been delivered, glucose infusions with delayed initiation of
intravenous insulin can be used as guided by the maternal
glucose levels.
 Immediately after placental delivery, a large reduction in
insulin requirement occurs, and this must be anticipated to
avoid hypoglycaemia. Initial postpartum insulin needs are
generally as low as, or lower than, pre-pregnancy
requirements.

25.  All women should continue taking folic acid (started before
conception) to reduce the risk of neural tube defects. Some
experts recommend higher doses of folic acid for women
with high BMI or with diabetes.
 In the long term, therapeutic lifestyle changes such as diet,
exercise, and smoking cessation are important to reduce
the risk of cardiovascular disease.

26. Source: American Diabetes Association. Standards of
medical care in diabetes—2015. Diabetes Care.
2015;38(suppl 1):S1-S93.