This clinical practice guideline discusses the screening, diagnosis, and management of gestational diabetes. Key points include: - There is no consensus on the optimal screening approach for gestational diabetes. Common options include screening at the first prenatal visit or at 24-28 weeks. - Diagnosis is typically made through a 75g oral glucose tolerance test, with thresholds defined by the International Association of Diabetes and Pregnancy Study Groups. - Initial treatment involves medical nutrition therapy and glucose monitoring. Insulin therapy may be needed if targets are not met with diet and exercise alone. - Recommended insulin regimens include prandial insulin with meals or basal-bolus regimens. Monitoring frequency depends on

1. Clinical Practice Guideline
Gestational Diabetes
Iris Thiele Isip Tan MD, FPCP, FPSEM
MS Health Informatics (cand.)
Clinical Associate Professor, UP College of Medicine
Section of Endocrinology, Diabetes & Metabolism
Department of Medicine, Philippine General Hospital
18 March 2010

2. AACE
A
AD
IDF CDA
P
DI
HAPO
GO
NICE
AS
IADPSG
Disclosure
None ...
Where guidelines disagreed, I
picked the one I agreed with ☺

3. 31/F obese pregnant
(pre-pregnancy BMI 30)
20 weeks AOG
Referred for rapid
weight gain of 5 kg in
the last 4 weeks
Her mother has
type 2 diabetes
S c re e n fo r G DM?

4. There is not sufficient
high-level evidence to
make a recommendation
for, or against, screening
for GDM.
US Preventive Services Task Force 2008
UK National Health Service 2002
Canadian Task Force on
Periodic Health Examination 1994
“Screening, diagnosis
and treatment of
gestational diabetes is
cost-effective.”
UK National Institute for Health
and Clinical Excellence 2008

5. No consensus on GDM screening
Who? When? How?

6. International Association of Diabetes
1998
and Pregnancy Study Groups
Recommendations on the Diagnosis
and Classification of Hyperglycemia
in Pregnancy. Diabetes Care
Mar 2010; 33(3):676-82.
cilitate
Umbrella organization to fa
collaboration
“This report represents
the opinions of
individual members of
the IADPSG Consensus
Panel and does not
necessarily reflect the
position of the
organizations they
represent.”

7. Overt Dia be te s First prenatal visit
in Preg na ncy
Measure FPG, A1c or
FPG >7 mmol/L
A1c >6.5%
random plasma glucose
RPG >11.1 mmol/L in all or only on high-risk
women
IASDPG Consensus Panel
Diabetes Care Mar 2010; 33(3):676–682.
If results not diagnostic of
overt diabetes and
FPG 5.1-6.9 mmol/L
(92-125 mg/dL) → GDM
FPG <5.1 mmol/L →
75-g OGTT at
24-28 wks AOG

8. 75-g OGTT thresholds
FPG 5.1 mmol/L (92 mg/dL)
1-h PG 10.0 mmol/L
(180 mg/dL)
Be nefit o f e a r ly te s t ing? 2-h PG 8.5 mmol/L
(153 mg/dL)
IASDPG Consensus Panel
Diabetes Care Mar 2010; 33(3):676–682.
75-g OGTT at 24-28 wks
Overt diabetes if FPG >7.0
mmol/L (126 mg/dL)
GDM if one or more values
equals or exceeds
thresholds
Normal if all values on
OGTT less than thresholds

9. First prenatal visit
Screen women at very
high risk using standard*
diagnostic testing.
* FPG, HbA1c, 75-g OGTT or random
plasma glucose
ADA Standards of Medical Care 2010
Very high risk
Severe obesity
Prior history of GDM or
delivery of LGA infant
Presence of glycosuria
Diagnosis of PCOS
Strong family history of
Type 2 diabetes

10. Greater than low risk
women
Test for GDM at 24-28
weeks AOG
Low risk women
No testing required
ADA Standards of Medical Care 2010
Low risk (must fulfill all)
Age < 25 years
Weight normal before pregnancy
Ethnic group with low DM prevalence
No known diabetes in first-degree
relatives
No history of abnormal glucose
tolerance
No history of poor obstetrical
outcome

11. 1996
IADPSG ADA ASGODIP
First 50-g GCT
FPG, HbA1c or FPG, HbA1c, 75-g
prenatal random plasma OGTT or random (low risk) or
visit glucose plasma glucose 75-g OGTT
(high risk)
Further GCT ➝ 100-g OGTT If GCT <130
75-g OGTT if FPG
testing <5.1 mmol/L 100-g OGTT (1-step) If 2-h OGTT
24-28 wks <140
100-g OGTT
Thresholds FPG >7 mmol/L
.0 FPG 95 mg/dL 75-g OGTT 2h
Overt diabetes 1-h 180 mg/dL 140 mg/dL
75-g OGTT any value 2-h 155 mg/dL
FPG 5.1 mmol/L (92 mg/dL) 3-h 140 mg/dL
1-h 10 mmol/L (180 mg/dL) at least 2
2-h 8.5 mmol/L (153 mg/dL)

12. 31/F obese pregnant
(pre-pregnancy BMI 30)
20 weeks AOG
Referred for rapid
weight gain of 5 kg in
the last 4 weeks
Her mother has
type 2 diabetes
FBS or 75-g OGTT?

13. 31/F obese pregnant
(pre-pregnancy BMI 30)
20 weeks AOG
75- g OGT T:
Fa stin g 102 ⤳ GDM
1 h PG 192 by FBS
2 h PG 155 criterion

14. Diet prescription
in GDM?
“Initiate MNT immediately
once diagnosed.”
AACE 2007

15. “All women with GDM
should receive
nutritional counseling by
a registered dietitian
when possible.”
ADA GDM Position Statement 2004
Choose where possible
CHO from low GI sources
Lean proteins including
oily fish
Balance of poly- and
monounsaturated fats
NICE 2008

16. If pre-pregnancy BMI >27,
restrict caloric intake to
<25 kcal/kg/day ...
... and take moderate
exercise (>30 min daily).
NICE 2008
Obese women (BMI >30):
30-33% calorie
restriction (to ~25 kcal/kg
actual weight/day)
Restrict CHO to 35-40%
of calories. ion Statement 2004
ADA GDM Posit

17. Monitor urine ketones
before breakfast to detect
starvation ketonuria
3 meals and 3 snacks
50-60% complex high
fiber carbohydrates
18-20% protein or at
least 75 g
<30% fats
ASGODIP 1996

18. “Non-caloric sweeteners
may be used in
moderation.”
ADA GDM Position Statement 2004

19. 31/F obese pregnant
(pre-pregnancy BMI 30)
20 weeks AOG
Ht 165 cm Wt 90 kg
TC R = 90 x 25 kc al/kg =
2250 kc al/day
3 me als an d 3 sna cks
CH O (50%) 281 g
CH ON (20%) 112 g
fats (30%) rest
Ur ine keton es at ff- up

20. Blood glucose
monitoring?
“SMBG is essential
during pregnancy.”
Canadian Diabetes Association 2008

21. “Daily SMBG appears to
be superior to intermittent
office monitoring of
plasma glucose.”
ADA GDM Position Statement 2004
“For women treated with
insulin, limited evidence
indicates that
postprandial monitoring
is superior to preprandial
monitoring.”
ADA GDM Position Statement 2004

22. Both preprandial and postprandial
testing are recommended.
If on insulin, test at night because of
increased risk of nocturnal hypoglycemia.
Canadian Diabetes Association 2008

23. Patients should
intensively monitor BG
AACE 2007
Insulin therapy
Diet only Monitor BG 6x a day
Monitor BG 4x a day (before each meal* and
(prebreakfast and 1 h 1 h after the first bite of
after the first bite of food food at each meal)
at each meal)
* to determine insulin
dosage correction

24. “Urine glucose monitoring
is not useful in GDM.”
ADA GDM Position Statement 2004
“Urine ketone
monitoring may be useful
in detecting insufficient
or caloric or CHO intake
in women treated with
caloric restriction.”
ADA GDM Position Statement 2004

25. 31/F obese pregnant
(pre-pregnancy BMI 30)
20 weeks AOG
Diagnosed GDM
MNT started
Monitor CBG 3x a day,
alternate between
- prebreakfast and 1 h
after breakfast & lunch
- 1 h after meals

26. 31/F obese pregnant
(pre-pregnancy BMI 30)
20 weeks AOG
Diagnosed GDM
After 2 weeks
Preprandial CBGs
70-80 mg/dL
1h Postprandial CBGs
130- 150 mg/dL

27. How long can we wait before
declaring diet therapy a failure?

28. Consider insulin
when ...
Diet and exercise fail to
maintain glucose targets
during a period of 1-2 weeks
Ultrasound suggests incipient
fetal macrosomia (AC >70th
percentile)
NICE 2008

29. Glucose targets
Between 60 to 90 mg/dL (fasting) and
less than 120 mg/dL (1 hour after the first
bite of food at each meal)
AACE 2007

30. “HbA1c should not be
used routinely for
assessing glycemic
control in the second
and third trimesters of
pregnancy.”
NICE 2008

31. 31/F obese pregnant
(pre-pregnancy BMI 30)
20 weeks AOG
Diagnosed GDM
Preprandial CBGs
70-80 mg/dL
1h Postprandial CBGs
130-150 mg/dL
Start insulin to bring
down postprandial CBGs

32. Can we give
Metformin in GDM?
Ho w ab ou t
Gli ben cla mide?

33. Off-label use
Use of metformin or
glibenclamide during
pregnancy not an
approved indication
Discuss with patients
Canadian Diabetes Association 2008

34. Option of giving
metformin or
glibenclamide
Obtain and document
informed consent.
“... tailored to glycemic
profile of, and
acceptability to, the
individual woman.”
Me tfo rm in in Ges tat ion al Dia betes
(M iG) Stu dy NICE 2008

35. Combination
therapy
MiG study
Women taking
metformin (who had
insulin added) required
lower insulin dose
? metformin +
glibenclamide
IDF 2009

36. Insulin remains the
agent of choice
“In poorly resourced areas
of the world, the
theoretical disadvantages
of using oral glucose-
lowering agents ... far less
than the risks of non-
treatment.”
IDF 2009

37. Recommended
insulin regimens?
Prandial, basal bolus,
split-mixed? Analogues?

38. Initiate a basal-bolus
regimen if a patient
cannot maintain
glucose targets with
diet alone.
NPH insulin (basal) and
rapid-acting insulin at meals
Subcutaneous insulin
infusion with an insulin pump
AACE 2007

39. Insulin regimens
in GDM
Intermediate-acting insulin
30 min prebreakfast and
presupper + rapid-acting
insulin
3 injections of rapid-acting
insulin given 30 min before
each meal + intermediate-
acting OR long-acting
insulin at bedtime
ASGODIP 1996

40. Insulin therapy
in GDM
Initiating dose depends
on the blood glucose
May start daily insulin
dose 0.1-0.3 u/kg BW
ASGODIP 1996

41. Which type of insulin
and which regimen?
Discuss with patient.
“ ... rapid-acting insulin
analogues (aspart and
lispro) have advantages
over soluble human
insulin during
pregnancy ...”
NICE 2008

42. 31/F obese pregnant
(pre-pregnancy BMI 30)
20 weeks AOG
Diagnosed GDM
Ht 165 cm Wt 90 kg
Preprandial CBGs
70-80 mg/dL
1h Postprandial CBGs
130-150 mg/dL
Start prandial (regular)
insulin i.e. 4-6 units
premeals tid

43. How often to
follow-up?

44. Subsequent Visits
Every 2 weeks for
Glycemic control: check
2-h PPBG
Obstetric complications:
macrosomia, IUGR,
preeclampsia, and
hydramnios
ASGODIP 1996

45. Ultrasound
At first visit to determine
age of pregnancy
At 20-22 wks to detect
malformations
At 32-34 wks to monitor
growth
ASGODIP 1996

46. Management
during labor and
delivery

47. Protocol for
Spontaneous Delivery
Infusion of 500 ml 5%
dextrose/saline x 4 h
CBG q 4h
Give short-acting insulin for
CBG >140 mg/dL
- Dose equal to mmol of CBG
i.e. 12 u for 12 mmol/L
- Dose equal to 1/20th of mg/dL of
CBG i.e. 12 u for 240 mg/dL
Omit insulin for CBG <140
mg/dL ASGODIP 1996

48. Maternal hyperglycemia
is the main cause of
neonatal hypoglycemia
Insulin is still required before
active labor; SC or IV to
maintain BG 70-90 mg/dL
Infuse glucose 2.5 mg/kg/
min
Measure CBG q hourly
Double the glucose infusion
for the next hour if BG <60
mg/dL
Give regular insulin SC or IV
for BG >120 mg/dL AACE 2007

49. After delivery
Resume diet
GDMs with high insulin
requirements during
pregnancy should have
glucose profiles
Give insulin if BG persistently
high (>200 mg/dL)
ASGODIP 1996

50. Postpartum
follow-up

51. Reclassify at least 6
weeks after delivery
Reassess q 3 years if
normal BG postpartum
Test for diabetes annually
if with IFG or IGT
postpartum
ADA GDM Position Statement 2004

52. All patients with prior
GDM should be educated
re: lifestyle modifications
Maintain normal body
weight: MNT and physical
activity
Women with IFG or IGT
postpartum: intensive
MNT and individualized
exercise program
ADA GDM Position Statement 2004

53. Planning subsequent
pregnancies
Plan future pregnancies in
consultation with health
care provider
Assess glucose tolerance
prior to conception to
assure normoglycemia at
time of conception
Canadian Diabetes Association 2008

54. “As always, solutions of an
immediate problem raise questions
for the future.”
Robert G. Moses, MD

55. ht tp:/ w w. slide sh are.net/i sip ta n
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Thank You
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