Gestational diabetes mellitus

1. Benha University Hospital, Egypt
Aboubakr Elnashar

2. Outline
•Physiological changes
•Definition
•Prevalence
•Adverse outcome
•Screening
•Diagnosis
•Medical management
•Obstetric management
•Conclusion Aboubakr Elnashar

3. Physiological changes
Pregnancy is a state of physiological insulin
resistance & relative G intolerance
1. GT: decreases progressively with increasing gestation
{anti-insulin hormones secreted by the placenta; h pl
lactogen, glucagon, cortisol}.
2. Increased insulin requirements :
Development of GDM
Aboubakr Elnashar

4. 3· Glucose handling is altered:
FBG: decrease
G levels following a meal or glucose load:
increase compared to the non-pregnant state.
The renal tubular threshold for glucose: falls:
glycosuria
Glycosuria is not a reliable diagnostic tool
4. Starvation: early breakdown of triglyceride:
liberation of fatty acids & ketone bodies.
Aboubakr Elnashar

5. COH intolerance with onset or first
recognition during the present
pregnancy (American Diabetes Association, 2002)
So includes pre-existing but previously un
recognized diabetes.
D in
pregnancy
Pre-
existing
IDDM NIDD
Gestational
Preexisting TrueAboubakr Elnashar

6. •Depend on:
population studied
diagnostic tests employed
4.0- 14.0%
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7. Severe forms of GDM are linked to adverse outcome
(Hyde et al, 2005).
The perinatal mortality & morbidity are increased in untreated
GDM (large randomized Australlian study)
Aboubakr Elnashar

8. .
Maternal problems
•Pregnancy
Anxiety
Abnormal wt gain
PET
Birth trauma (secondary to
macrosomia)
Increased rate of CS
•Later
Increased rate of T2DM,
hypertension, CVD
Problems in offspring
•Fetal
?Malformation
IUFD
Macrosomia
Shoulder dystocia/hypoxia-
acidosisl/Erb's palsy
Iatrogenic prematurity
•Neonatal
Hypoglycaemia
Polycythaemia
Hyperbilirubinaemia
Hypocalcaemia
Cardiomyopathy
•Adult
Obesity
Increased rate of T2DM, hypertension,
CVD, ?Breast cancerAboubakr Elnashar

9. Abnormal fetal growth
•Macrosomia: B. wt > 4000 g regardless of
gest age or sex, or organ wt
Aboubakr Elnashar

10. •Etiology:
-Maternal hyperglycaemia:
Fetal hyperinsulinaemia: stimulate f growth (Pederson
hypothesis).
-Mat obesity
-Mat hyper-triglyceridemia
-Recent studies:
The relation between mat glycaemic control & f wt is v
weak.
Only a minority (25%) of infants of mothers with
hyperglycaemia become macrosomic.
Aboubakr Elnashar

11. •The growth response of the fetus to
hyperglycaemia is dependent upon whether the
fetus has gene defect or not.
Gene HNF4A, which is associated with diabetes
Genetic test for HNF4A of the baby with
low blood-sugar & family history of diabetes:
Early diagnosis of maturity-onset diabetes of the
young.
Aboubakr Elnashar

12. Fetal malformation
•Pre-existing DM:
Higher rate: cardiac, skeletal, NTD.
Etiology: poor glycaemic control at the time of conception
•GDM:
Normal rate {euglycaemic at the time of conception}.
Recent studies: Higher rate
Aboubakr Elnashar

13. Risk of major
malformation (%)
Normal
population
2
Preexisting DM 10
GDM 4
(Schaefer et al, 1997; Aberg et al, 2001; Sheffield et al, 2002)Aboubakr Elnashar

14. Etiology: Unknown
•FBS at time of diagnosis of GDM is
high (Schaefer et al. 1997)
•Some cases are (undiagnosed)
pre-existing T2DM & occult
hyperglycaemia at the time of
organogenesis
Aboubakr Elnashar

15. Fetal death & occult GDM
Perinatal mortality rate: 10-fold higher
(Rudge et al, 2000)
Occult GDM (GDM pass undetected)
contributes to a large proportion of
unexplained late IUFD (Robson et aI, 2001)
Aboubakr Elnashar

16. Long-term health problems for offspring
obesity, diabetes & CVD (Sattar & Greer, 2002)
•Genetic predisposition: GDM is transmitted
through the maternal line (Knowler et al, 1985)
Aboubakr Elnashar

17. Maternal long-term health problems
•T2DM:
General population: 8%.
GDM: 30% (Kaufmann et al, 1995).
GDM is a transient form of T2DM.
•CVD & premature death.
Aboubakr Elnashar

18. Aboubakr Elnashar

19. Controversy:
•Advantage and disadvantage of
detecting GDM
•What ?
•When?
•WHO?
•Recommendations?
Aboubakr Elnashar

20. Advantage
1.GDM is associated with macrosomia
and adverse effects on pregnancy.
So prevention of this adverse effects
2. A small proportion are in fact
unrecognized preexisting D. , are at
risk of all complications of D.
Aboubakr Elnashar

21. 3. GDM is associated with increased risk
(50%) of T2D within 10-15 ys.
Prevention or delay development of T2DM
(de Soares et al, 1997). by
Medical or life-style intervention resulted in
reduction of DM
• In Finland (Tuomilehto et al, 2001)
Individuals with impaired glucose tolerance:
dietary modification: 50% reduction of risk DM (11% Vs 23%).
• In Washington (The Diabetes Prevention Research Croup, 2002)
individuals at high risk of T2DM:
life-style modification reduced risk of DM by 58%
Metformin reduced it by 31%.
Prevention of microvascular complication
by early diagnosis & careful follow upAboubakr Elnashar

22. Disadvantages
Increase CS rate
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23. What?
Ideal screening test:
Sensitive
Specific
Simple
cheap
convenient.
Aboubakr Elnashar

24. Screening tests
Random blood glucose (RBG):
Within 2 h: 125 mg/dl
2-6 h: 100 mg/dl
Fasting blood glucose (FBG):
86 mg/dl
1-h 50 g glucose challenge test (GCT)
140 mg/dl
2-h 50 g glucose challenge test .
75 g glucose tolerance test (GTI)
Glycated haemoglobin or Fructosamine: no role in diagnosis of
GDM, useful in monitoring of effective glycemic controlAboubakr Elnashar

25. •GCT:
High sensitivity (69%),
Specificity (91%),with a cut off of
140 mg/dl (7.8 mmol/l).
Poorly tolerated (induce nausea).
Time consuming
Expensive. Aboubakr Elnashar

26. •FBG:
High sensitivity (81%)
Good specificity (76%) with a cut off of 86 mg/dl (4.8 mmol/l)
(Perucchini et al, 1999)
Easier,
Cheaper
More acceptable .
Can be applied to all pregnant women
more than once during pregnancy.
Suitable for screening
Aboubakr Elnashar

27. When?
•The latter in pregnancy: higher
detection rate {GT deteriorates with
increasing gestation}
•The earlier in pregnancy the GDM is
diagnosed: the greater the potential to
treat hyperglycemia & improve outcome.
Aboubakr Elnashar

28. WHO?.
•Universal: screening all pregnant
The only approach that will detect virtually all
cases (Griffin et al,2000 ).
•Selective: screening high-risk women
For reasons of cost and convenience,
Disadvantage:
missing up to 50% . Aboubakr Elnashar

29. •Risk factors for selective screening
Maternal age >30
Family history of T2DM
Non-white ethnic origin
Obesity
Smoking
Increased wt gain in early childhood
PCOS
Previous large infant (> 97th centile)
Previous unexplained still-birth
Aboubakr Elnashar

30. Recommendations
•Diabetes UK: Routine screening
Urine testing at every ANC visit
RBG at booking, at 2l W and if glycosuria.
75 g GTT if FBG > (110mg/dl)6.1 mmol/L or RBG> (125mg/dl) 7.0 mmol/L within 2
h of food
•Scottish Guidance Network: Routine
screening
Urine and RBG at every ANC visit
Aboubakr Elnashar

31. •American Diabetic Association: Selective
screening
Age> 25' years'
Overweight before pregnancy
Ethnic group with high prevalence GDM
Diabetes in first-degree relative
History of abnormal glucose tolerance'
History of poor obstetric outcome' .
With 50 g GCT. confirm with 100 g GTT
•National institute for Clinical Excellence:
No routine screening
Aboubakr Elnashar

32. •Society of Obstetricians and
Gynecologists of Canada:
Routine screening at 24-28 w with 50 g GCT
with cut off 7.8 mmol/l .
No screening as no definitive evidence to
support
Selective screening: as early as possible
with repeat at 24-28 w
Aboubakr Elnashar

33. Aboubakr Elnashar

34. The 75 g OGTT
using recent WHO criteria is now used
almost universally throughout the world
as the gold standard test for diagnosing
GDM (Piercy, 2006) .
Fasting venous & capillary blood glucose are similar.
After a meal or a glucose challenge, capillary are higher than venous levels.
It is not necessary for both values to be
abnormal
Plasma glucose Mg/dl
Fasting 100
2-h 145
Aboubakr Elnashar

35. No need for GTT
FBS 125mg/dl (7.0 mmol/l) or
Random venous plasma glucose 200
mg/dl (11.1 mmol/l) if confirmed on a
subsequent day
Aboubakr Elnashar

36. I. Diet
II.Exercise
III.Insulin
IV.Hypoglycemic drugsAboubakr Elnashar

37. I. Diet
•The first line therapy for 1-2 w
•3 meals & 4 snacks with last snack at bed time
{minimize the overnight hypoglycemia &
starvation ketosis (during pregnancy, there is
accelerated starvation)} (Maternal Nutrition of the National Research
Council, 1995)
•Caloric needs acc to BMI (The American Diabetes Association, 2003)
< 30 kg/m2: 30 Kcal/kg
>30 kg/m2: 25 Kcal/kg
Aboubakr Elnashar

38. •Carbohydrates 40%
Protein 30%,
Fat 30% (Garner, 1995).
•Concentrated sweets & added sugars
should be eliminated.
•Complex CHO with high fiber contents
are preferable {slower glucose rise after
ingestion} (American Diabetes Association, 2003).
Aboubakr Elnashar

39. II. Exercise
•Reduce insulin requirement by as much as
50%. The effect appears after 4 w.
•1h after mealtimes.
•For 20-30 min
•Upper extremity or lower extremity ms
excerises while recumbent do not
increase uterine contractions (Durak et al, 1990
;de Veciana and Mason, 2000).
Gentle aerobic exercise
Walking (Homko et al, 1998).
Aboubakr Elnashar

40. Aboubakr Elnashar

41. III. Insulin
Aboubakr Elnashar

42. Rapidly acting analogues (Lispro, Aspart):
has been approved during pregnancy (Metzger et al, 2007,
Mathiesen et al, 2007)
1. Superior than regular insulin in controlling
postprandial hyperglycemia (Heinemann et al, 1998)
2. Rapid onset of action: Given immediately
before eating: improves compliance & patient
satisfaction
3. Category C medication
Aboubakr Elnashar

43. Long acting analogues (glargine,
detemir)
Has not been approved in pregnancy
Aboubakr Elnashar

44. Indications:
1.
2. Failed dietary treatment
3. AC >95th centile between 29 & 33 W
Despite good glycemic control
Reduce macrosomia from 45% to 14% (Buchanan et al, 2004)
whole blood
glucose mg/dl
Plasma glucose
mg/dl
Fasting 95 105
1h postprandial 140 155
2 h postprandial 120 135
Aboubakr Elnashar

45. IV. Oral hypoglycaemics
•Not recommended for use in pregnancy.
1. Early agents crossed the placenta & stimulated
fetal insulin secretion: fetal macrosomia &
hyperinsulinaemic hypoglycaemia in neonates.
2. Major congenital malformations in animals
(Greene, 2000)
Aboubakr Elnashar

46. •Advantage
1. Ease of administration
2. Ease of storage,
3. Convenience:
No injections.
No infection
Continued
4. Cost.
Recent studies evaluating its use in pregnancy
Aboubakr Elnashar

47. Glyburide: Micronase, 5 mg Upjon
2nd generation sulfonyl urea
in vitro studies: minimal maternal-fetal transfer
(Garcia et al, 2003)
Glyburide Vs Insulin (Langer et al, 2000).
404 women with GDM that required treatment, were randomly assigned between 11& 33
w to receive 5-20 mg/d glyburide or insulin
•No significant differences:
Macrosomia
N. Hypoglycemia
Admission to the NICU
Fetal anomalies
•Glyburide was not detected in the cord serum
effective & safe alternative to insulin
Aboubakr Elnashar

48. Metformin
the only available biguanide.
In contrast to glyburide, metformin does cross the placenta.
Mechanism:
Mainly by decreasing gluconeogenesis & by increasing peripheral utilization of glucose.
At therapeutic doses, hypo glycaemia does not occur when used in isolation but it may exert a
hypoglycaemic action when given in overdose.
Side effects:
1. lower incidence of wt gain & weight loss may occur.
2. Gastrointestinal side-effects are common initially but usually settle within a few days.
3. Vitamin B12 deficiency
4. Lactic acidosis, extremely rare & only occurs in vascular disease, renal patients,PET
Aboubakr Elnashar

49. 3 studies
The accumulated experience is smaller with less than
200 women treated.
Some disappointing outcome data.
•Favorable PNMR but the comparison was with untreated patients for whom the PNMR
was 146/1000.
Increase in neonatal jaundice (Coetzee & Jackson, 1979)
•Met, tolbutamide, insulin: Glycaemic control was comparable to insulin-treated patients
in both groups but Met was associated with a 3-fold increase in the incidence of PET
and' an increased PNMR compared with those on tolbutamide and insulin (Hellmuth et
al, 2001)
•Met Vs insulin: both similar ability to control hyperglycaemia but Met was associated
with a higher CS and more neonatal hypoglycaemia (Hauge et al, 2003)
These outcomes may well reflect small study sizes but the safety of Met is not
established and it is advocated that it should not be used for this purpose outside
of well designed research studies (Dornan & Hollis, 2001; Glueck et al, 2002)
Aboubakr Elnashar

50. Antenatal
1. Glycemic control
2. Fetal wellbeing
3. F. wt:
4. Delivery:
Intrapartum Postpartum
1. Glycemic control
2. Assessment
3. Breast feeding
4. Contraception
5. Prevention
Aboubakr Elnashar

51. A. Antenatal
Goals:
Maintain Euglycemia
Prevent macrosomia
Glycemic control
<32 w: Significant reduction
>32W: No reduction (Sameshima et al, 2000).
Aboubakr Elnashar

52. I. Glycemic control.
a. Blood glucose:
• Objective:
Capillary blood glucose Mg/dl(mmol/L)
Fasting <100(5.5)
1 Hour <140 (7.8)
2 Hours <125 (7.0)
Aboubakr Elnashar

53. • Preprandial OR postprandial?:
In non-pregnant: Preprandial is preferred
In pregnancy: Post prandial is preferred (Konje, 2004)
1. The fetus is more sensitive to hyperglycemia than to
nadirs of glucose values
2. F & preprandial BG values are often normal even
before treatment
3. Postprandial monitoring:
improved glycaemic control
decreased rate of macrosomia, CS, neonatal
hypoglycaemia (de Veciana et al, 1995).
Aboubakr Elnashar

54. •1h or 2h post prandial?:
No agreement (Ahn & Hibbard, 2005),
but most authorities advocate 2h postprandial
Aboubakr Elnashar

55. • Frequency:
weekly up to 7 times daily
Mild: Twice daily
Severe: 4 readings (Fasting, 2 h after breakfast, lunch &
dinner)
• Self-tested blood glucose, using hand-held digital read-
out devices
Aboubakr Elnashar

56. Cap Bl sugar FBS 2hPP
60 – 90 NO
NO
91 – 120 1 Unit
121 – 150 2 Units 1 Unit
151 – 200 4 Units 2 Units
201 – 250 8 Units 4 Units
251 – 300 10 Units 8 Units
301 – 350 12 Units 10 Units
351 – 400 14 Units 12 Units
> 400 Call Doctor 14 Units
Aboubakr Elnashar

57. b. Glycosylated hemoglobin A1C:
-Retrospective assessment of glycemic
control. Evaluates blood glucose over the
life span of the RBC i.e. 120 days.
-Due to enhanced erythropoiesis during
pregnancy, it is done every 6 w
Excellent control: <7%
Fructosamine: Not useful {low sensitivity}
Aboubakr Elnashar

58. II. Fetal wellbeing:
Indications:
Insulin is required
Poorly controlled diabetics
Hypertension
History of IUFD
Tests: no reliable test. A combination of tests must be employed.
Kick chart, NST, CST, FBP, Doppler
Regimen
Twice weekly NST with once weekly AFI or FBP
Kick chart: At least 10 kicks/2h
Aboubakr Elnashar

59. III. F. wt: Screening for macrosomia
•Both cl & US are inaccurate (±10-20%).
•Clinical is more accurate than US (Sherman et al, 1998)
•US: huge variation in sensitivity (24-88%) &
specificity (60-98%) (Reece et al, 1995).
•Novel methods (cheek-to-cheek diameter, fetal thigh SC tissue at the level
of the femoral diaphysis, thigh soft tissue/FL ratio, upper arm soft tissue
thickness, EFW derived from a formula incorporating AC, FL & upper arm soft
tissue thickness): Not superior to clinical & routine US (Chauhan et al,
2000)
• The best single measurement: Serial measurements of
AC Aboubakr Elnashar

60. IV. Delivery:
• Time:
In a well controlled GDM, delivery should be considered at 38-40w
There is very little evidence to support either induction of labor at 38w
or expectant management (Cochrane Syst Rev 2000)
Induction at 38w in insulin requiring GDM showed lower rate of:
macrosomia (10% Vs 23%),
CS (25% Vs 30%) and
Shoulder dystocia (0% Vs 3%) (Kjos et al, 1993).
Delivery before 38W:
Poor glucose control
Poor compliance
Co morbidities e.g. hypertension
Corticosteroids:
<36 w Aboubakr Elnashar

61. •Mode:
Elective CS:
Estimated F wt>4500 g (ACOG,2003 )
4000 & 4500g (Inzucchi, 1999).
Aboubakr Elnashar

62. B. Intrapartum
•The target glucose level: 75-145 mg/dl (4-8 mmol/l)
•On diet: Bl glucose/h
On insulin:
<20 U/d: No need for insulin (Piercy, 2006)
>20 U/d: IV dextrose & insulin
Sliding scale
Aboubakr Elnashar

63. C. Postpartum
1.Glycemic control
Stop Insulin: Most patient will have
normal glucose level.
Insulin be reinstituted as needed .
Aboubakr Elnashar

64. 2. Postpartum Assessment
•Unrecognized pre GDM is suspected when:
1-Initial fasting >125 mg/dl,
2-GDM during first trimester
•75 g OGTT 6 w following delivery (ACOG, 2003)
•FBG: if abnormal: OGTT
Aboubakr Elnashar

65. 3. Breast feeding:
should be encouraged (Gange et al, 1992).
. Reduces the insulin requirement by 25%
. Breast- feed babies have a much lower
risk of developing DM (Jovanovic,1998)
Aboubakr Elnashar

66. 4. Contraception
•Copper IUCD, Mirena:
not associated with PID
(Kimmerle et al, 1993 ; Kjos et al,1994)
•DMPA:
Deterioration of CHO tolerance
increase risk of diabetes
•NORPLANT:
No deterioration
(Fahmy et al, 1991 ; Konje et al,1992; Singh et al,1992)
Aboubakr Elnashar

67. GDM:
Low-dose COCs
•didn't influence development of Diabetes
(Kjos et al,1998)
•Non smoker, <35 years, healthy: no hypertension, nephropathy,
retinopathy, or other vascular disease.
Progestin-only Pill
with breast feeding: 3 fold risk of diabetes
(Kjos et al,1998)
Should be prescribed with caution, if at all.
Aboubakr Elnashar

68. 5. Prevention of GDM
1.Preconceptual counseling.
The risk of future DM
Life style advice regarding diet & exercise
Avoid obesity
Obese to lose weight
It may also prevent miscarriage, fetal malformation
2. Metformin before & during pregnancy in women with
PCOS {high rate of GDM}.
l0-fold reduction (Glueck et al.,2002)
Significant reduction in first trimester miscarriage (Glueck et al, 2002; Jakubowicz et al,
2002)
Increased live birth rate with no increase in fetal abnormalities or teratogenicity
Aboubakr Elnashar

69. The differences between the results for the prevention
and treatment of GDM are of interest.
May reflect different responses because of different
pathophysiologies of prediabetes and GDM.
It seems that prevention may be better than control.
Aboubakr Elnashar

70. Aboubakr Elnashar

71. •GDM may be associated with a higher rate of
fetal malformation, macrosomia; birth trauma &
neonatal hypoglycaemia.
•Longer term health risks to the mother have
been confirmed.
•GDM is not itself without risk; the incidence of
CS is increased.
•Early screening should be done in women with
identified risk factors.
•Fasting blood glucose is both highly sensitive &
simple to implement. Aboubakr Elnashar

72. •The goal of therapy is maintaining
euglycemia & preventing macrosomia.
•Glycemic control: FBS <100 mg/dl, 2 h
postprandial <125 mg/dl & HbA1c <7%.
•Management with diet in first instance,
followed by insulin in resistant cases.
•Induction of labour should be considered
by 38w in insulin requiring GDM.
• 75 g OGTT 6 w after delivery is
recommended. Aboubakr Elnashar

73. Thank You
Prof. Aboubakr Elnashar
Aboubakr Elnashar