Gestational Diabetes Mellitus

1. Gestational Diabetes Mellitus
Dr Susanta Kumar Behera
Asst Professor
Dept. of O&G

2.  GDM is defined as carbohydrate intolerance
of variable severity with onset on first
recognition during the present pregnancy
irrespective of the fact that the condition
persists after pregnancy or not or insulin is
used or not for treatment.
 Includes some women previously
unrecognised overt diabetes.

3.  Usually presents late in the second or
during the third trimester.
 Majority of women with GDM (>50%)
often ultimately develop overt diabetes by
next 15 to 20 years.

4. CARBOHYDRATE METABOLISM IN PREGNANCY
 Placental glucose transport depends on GLUT-1.
 Principal Glucose transporter GLUT-1 is located in
placental syncytiotrophoblast.
 Pregnancy is a diabetogenic condition due to
progressive increase in the Insulin resistance.
 Diabetogenic Effects of pregnancy as follows 

5. 1. INSULIN RESISTANCE
 Production of HPL, Cortisol, Estriol,
Progesterone all of which have anti-insulin
action.
 Increased Destruction of Insulin by kidney
and placenta(Insulinase)

6. 2. INCREASED LIPOLYSIS
 Mother utilises fatty acids for her calorie
needs sparing glucose for the foetus.
 Pregnancy is a state of chronic low grade
inflammation(associated with increased
circulating Level of CRP & IL-6).

7.  In early pregnancy there is an increased risk of
hyperglycemia due to increased insulin
sensitivity.
 Nausea and vomiting common in the 1st
trimester contribute to reduced intake that can
cause hypoglycemia.
 When the insulin resistance starts occurring in
the 2nd & 3rd trimester to provide nutrition to
the growing fetus there occurs marked
hyperglycemia.

8. GLYCOSURIA IN PREGNANCY
 During pregnancy renal threshold is
diminished due to combined effect of
increased GFR & impaired tubular
reabsorption of glucose.
 Present most commonly in mid Pregnancy.

9. Development of Carbohydrate intolerance
during pregnancy.
Pre-GDM or Overt Diabetes
Denotes conception in a women who is already
a diabetic.
If there is absence of documentation in pre-
conception period criteria met in first/early 2nd
trimester is considered to diagnose overt
diabetes.

11. Overt Diabetes
A Patient with symptoms of polyuria, polydypsia,
weight loss and random plasma glucose level of 200
mg/dl or more is considered Overt Diabetes.
According to American Diabetes Association(ADA)
diagnosis is positive If-
– Fasting Plasma glucose > 126 mg/dl
– 2 hr PPBS(75g) value > 200 mg/dl
– HbA1C > 6.8%

12. White’s Classification of Diabetes in pregnancy
Based on
–Patient’s condition before pregnancy
– Age of onset
–Duration of Diabetes
–Presence of complications

14. Reasons of development of GDM
Insulin resistance increases from the 2nd
trimester due to pregnancy hormone and
glucose levels rise in women who don’t have
that enough. pancreatic reserve for insulin
production specially in women with family
history of Diabetes and PCOD.

15. Risk factors for GDM
a) Positive family history of Diabetes (Parents
or siblings). Family history should include
uncles, aunts, and grand parents.
b) Having a BMI of ≥30 or overweight baby of
4 kg or more.
c) Previous GDM or still birth with pancreatic
islet hyperplasia revealed on autopsy.
d) Unexplained perinatal loss.

16. e) Presence of polyhydramnios or recurrent
vaginal candidiasis on present pregnancy
-Women with PCOS
-Hypertension (140/90 mm Hg)
f) Persistent glycosuria
g) Age over 30 years
h) Obesity
i) Ethnic Group ( East Assam, Pacific)

17. SCREENING AND DIAGNOSIS OF DIABETES
 Universal screening of all pregnant women in GDM
is now recommended (ACOG 2018). If selective
screening is done 50% cases of GDM maybe
missed.
 All pregnant women should be screened for GDM
irrespective of risk factors.
 Screening is done at 24-28 weeks of gestation.
 Early screening is recommended (ACOG , ADA) for
women with high risk factors.

19. Who Should be Screened Early?
 Overweight with BMI of 25 and one or more of the following
 Physical inactivity
 Family history of diabetes – 1st degree relative (parent or
sibling)
 Previous pregnancy history of GDM/ Macrosomia (≥ 4000 g)
 Hypertension (140/90 mm Hg
 HDL cholesterol ≤ 35 mg/dl (0.90 mmol/L)
 Fasting triglyceride ≥ 250 mg/dL (2.82 mmol/L)
 PCOS
 Insulin resistance (e.g., acanthosis nigricans, morbid obesity)
 Hgb A1C ≥ 5.7%, impaired GTT
 Cardiovascular disease

20. INTERNATIONAL ASSOCIATION OF DIABETES IN
PREGNANCY STUDY GROUP(IADPSG) & AMERICAN
DIABETES ASSOCIATION (ADA) CRITERIA
Done at 24-28 weeks
One step diagnosis: FBS followed by 75 OGTT
 FBS sample : 92
 1 hr sample : 180
 2 hr sample : 153
Diagnosis of GDM is made if ≥ 1 value is abnormal

21. ACOG (based on NIH consensus panel findings)
supports the ‘2 step’ approach (24 to 28 week)
Step-1(Screening test):1 hour venous glucose
measurement following 50gm oral glucose solution)
< 140 mg/dl : Normal
> 200 mg/dl : GDM confirmed
≥140 mg/dl,< 200 mg/dl : ?GDM : 2nd step

22. Step-2(Diagnostic test):100gm 3 hour oral
glucose tolerance test (OGTT)
– FBS sample : 95
– 1 hr sample : 180
– 2 hr sample : 155
– 3 hr sample : 140
Diagnosis of GDM is based on 2 abnormal
values on the 3 hour OGTT

23. DIPSI GUIDELINES
ACCORDING TO GOVT OF INDIA
 First testing should be done during first
antenatal contact as early as possible in all
pregnancies
 Universal screening for GDM is performed
due to high risk of GDM
 1ST screening : 1st Antenatal visit

24.  2nd screening : 24-28 wks of pregnancy
 Fasting – Not Needed
 Irrespective of previous meals, 75gm of
glucose in water is given

25.  Blood Glucose level are checked
after 2 hr-
>140 but < 200 mg/dl : GDM
>200 mg/dl : Pre-Gestational DM
 Quantity of water : 300ml can mix
to be consumed within 5 minutes.

26.  If patient vomits after glucose intake 
- within 30 mins – repeat testing next day
- after 30 mins – continue with the test
 If patient’s first Antenatal visit is being 28
weeks : Only one test should be done

27. COMPLICATIONS OF GDM
MATERNAL COMPLICATIONS
1. Increased chances of pre-eclampsia
(25%)
2. Abortion(Recurrent spontaneous abortion
may be associated with uncontrolled
diabetes)
3. Infections- UTI & Vulvovaginitis

28. 4. Polyhydramnios (25-50%) is a common
association(Large baby, large placenta, fetal
hyperglycemia leading to polyuria, increased
glucose conc. of liquor irritating the amniotic
epithelium or increased osmosis)

29. 5. Maternal distress may be due to the
combined effect of a oversized fetus and
hydramnios.
-Diabetic Retinopathy
-Diabetic neuropathy
-Diabetic nephropathy

30. Remote Complications of mother
- Reoccurrence occurs in subsequent
pregnancies in about 50% cases.
- 50% of GDM develops overt diabetes in the
ensuring 20 years

31. FETAL AND NEONATAL
1. Fetal Macrosomia
2. Increase chance of fetal death
3. Hyperbilirubinemia
4. Hypoglycemia
5. Hyperviscocity Syndrome
6. Hypocalcemia
7. Fetal congenital anomaly
8. Childhood and adult onset obesity

32. What Are Glucose Target Levels?
ACOG and ADA recommend the following
target levels to reduce risk of macrosomia
– Fasting or preprandial blood glucose values < 95
mg/dL
– Postprandial blood glucose values < 140 mg/dL
at 1 hour and < 120 mg/dL at 2 hours

33. MANAGEMENT
Pre-conceptional counseling
– Goal : tight control of diabetes before onset
of pregnancy.
– Folic acid supplementation (5mg/day).
– Women with pre-existing diabetes should be
advised to achieve a HbA1C ≤ 6.5% prior to
conception.
– Reduces the risk of major fetal malformations
and other pregnancy complications.

34. ANTENATAL CARE
 Pre-Gestational/ Gestational diabetes :
Anomaly scan at 18-20 weeks (same as all
pregnant women)
 At least 2 growth scans – At 28-30 wks and
34-36 wks ( minimum gap- 3 weeks)
 PGDM/GDM – Foetus has macrosomy 
Growth scan
 USG is repeated along with ECHO at 20-22
wks of gestation.

35.  GDM+controlled blood sugar & no
complications
 GDM+Not controlled blood sugar & no
complications like high BP
 Follow regular antenatal visits
• 2
nd
trimester- 2 weekly visit
• 3
rd
trimester – weekly visit

36. At each visit check
– BP(Increased risk of pregnancy induced
hypertension, Proteinuria, Polyhydramnios)
– Urine routine microscopy in each trimester
(UTI, Vaginal Candidiasis, Asymptomatic
bacteriuria)
– Fetal Growth
– Due to higher risk of pre-eclampsia low dose
Aspirin 150mg daily started since 12 weeks of
gestation.

37.  Start fetal growth monitoring from 32 weeks
(increased risk of IUD & Still birth)
 Daily fetal movement count by the mother.
Advise the mother to lie in left lateral position
after meals. Keep a count of fetal movements.
 Non Stress Test – Weekly
 Biophysical/modified biophysical profile –
Weekly
 Doppler USG of umbilical artery. Significantly in
condition with uteroplacental insufficiency such
as PIH & IUGR.

38. Weight Category BMI (Kg/m2) Energy requirement
(Kcal/Day)
Under weight < 18.5 Energy requirement as
per level of activity + 500
kcal/day
Normal weight 18.5 – 24.9 Energy requirement as
per level of activity
Over weight 25 – 29.9 Energy requirement as
per level of activity
Obese (Grade I, II, III,
IV)
> 30 Energy requirement as
per level of activity – 500
kcal/day

39. Calories as per Pre-pregnant weight
Pre-Pregnant
weight
BMI (Kg/m2) Total Weight gain
range (Kg)
Normal weight 18.5 – 24.9 11.5 – 16 kg
Under weight < 18.5 12.5 – 18 kg
Over weight 25 – 29.9 7 – 11.5 kg
Obese (Grade I, II, III,
IV)
> 30 5 - kg

40. Total Calories (3 major meals and 2-3 snacks)
should be divided as follows :
 Carbohydrates - 40%
 Fats – 40% (Saturated fat < 10% + Cholesterol
< 300 mg/day)
 Protein – 20%

41. MANAGEMENT OF GDM
Pregnant women with GDM
Medical Nutrition Therapy(MNT) & excercise
2 hr PPBS
After 2 weeks
<120 mg/dl
Continue MNT and
excercise
≥120 mg/dl
Start oral antidiabetic(Metformin)
Or
Start insulin
Monitor 2 hr PPBS
every month and
manage according to
high risk protocol
Monitor FBS & 2 hr PPBS every third
day(insulin)/ biweekly(Metformin) and adjust
dose to have target blood sugar level
Manage according to high risk protocol

42. DOC for diabetes in pregnancy – Insulin
National guidelines
INDICATIONS FOR STARTING INSULIN :
a) GDM patients if after 2 wks of management,
Post prandial (PP value) > 120 mg/dl.
b) Pre-gestational diabetes patients from day-1
of pregnancy.
c) 2 hr PP Value > 200 mg/dl in a pregnant
female.
INSULIN THERAPY

43. INTERNATIONAL GUIDELINES :
INDICATIONS FOR STARTING INSULIN :
Metabolic goals met but :
a) Estimated foetal weight is > 90% for
gestational age
b) Abdominal circumference is > 75% for
gestational age

44. Insulin
therapy

45. INSULIN INJECTIONS
– S/C route.
– 40 IU/ml vial, human premix insulin (30:70) &
insulin syringe (1ml/40IU) are used.
– Insulin should be stored in refrigerator between 4-
8 degree C (Not in freezer).
DOSE OF INSULIN
– Starting dose is calculated as per the 2hr post
prandial blood glucose level

46. BLOOD GLUCOSE LEVEL
(2 hr PP)
DOSE OF INSULIN
120-160 4U
160-200 6U
> 200 8U
 Insulin injection to be given 30 minutes before
breakfast.
 Every 3rd day fasting blood glucose level (FBS) & 2 hr
PPBS are checked
 If FBS > 95 mg/dl on 3rd day – Add 2 U dose before
breakfast

47.  If 2 hr PPBS > 120 mg/dl – Add 2 U dose
before breakfast.
 If both are deranged- Add 4 U dose
 Again in 3rd day measure fasting blood
sugar & 2 hr PPBS
 Keep titrating till the metabolic goals are met
: Continue the same dose of Insulin + MNT

48. ORAL HYPOGLYCEMIC AGENTS IN PREGNANCY
Oral Hypoglycemic agents are less potent
and cross placenta causing hypoglycemia
in the fetus therefore not used.
Exceptions- Metformin and Glyburides
can be used in Pregnancy

49. OBSTETRIC MANAGEMENT IN GDM
 Women with GDM that is controlled with only
diet and exercise should not be delivered before
39 weeks of gestation, if not indicated.
 For other reasons and spontaneous onset of
labor is waited up to 40 wks and then terminated.
 GDM cases well controlled by medications.
Delivery is recommended at 39 wks to 39 (6/7
days) wks of gestation.

50.  In cases of large baby > 4000 gm regarding route
of delivery. Patient should be counselled properly.
 In poorly controlled GDM delivery is considered
at 37 wks– 38 (6/7 days) wks.
 Delivery at < 37 wks is considered only after
features of poor glycemic control or abnormal
fetal surveillance.
 Mode of delivery – Planned vaginal delivery.
 Induction of labor is done as timing of delivery is
important.

51. INDICATIONS OF CESARIAN SECTION
a) Obstetrical Reasons : Fetal distress,
Contracted pelvis or estimated fetal wt
is > 4 kg in a diabetic patients.
b) Presence of vasculopathy (proliferative
retinopathy)
c) Obstetric complications like Pre-
eclampsia

52. INTRAPARTUM INSULIN REQUIREMENT
– Labor : Insulin requirement decreased
– GDM on insulin : Plasma glucose monitoring
during labor by a glucometer
– Day of induction of labor : Morning dose
withheld + 2 hrly monitoring plasma glucose
– IV infusion with NS + Regular insulin :
According to blood glucose level

53. BLOOD GLUCOSE
LEVEL
AMOUNT O INSULIN
ADDED IN 500 ML
RL/NS
BLOOD GLUCOSE
90 – 120 mg/dl 0 100 ml/hr (16
drops/min)
120 - 140 mg/dl 4U 100 ml/hr (16
drops/min)
140 – 180 mg/dl 6U 100 ml/hr (16
drops/min)
>180 mg/dl 8U 100 ml/hr (16
drops/min)

54. Post delivery Follow-up of GDM Patients(National
guidelines)
 Immediate Postpartum care : at increase risk
of developing type-2 DM in future.
 After delivery - Maternal Glucose is Normal (
Usually)
 3rd Day of delivery - fasting plasma glucose +
2 hour PPBS
– >48 hours - Discharged ( unlike normal PNC cases)
– 6 weeks post partum : 75g GTT - glycaemic status

55. Cutoff For normal blood glucose level
 Fasting glucose ≥ 126mg/dl
 75g OGTT 2 hour plasma glucose
a) Normal < 140 mg/dl
b) Impaired glucose tolereance 140-200 mg/dl
c) Diabetes ≥ 200 mg/dl
 As per ACOG guidelines, 75g GTT is due
between 4 - 12 weeks

56. Contraceptive Advices
–Barrier method of contractive is ideal for sparing
of hormones.
–Low dose combined oral pills - containing 3rd
generation progesterone are effective and have a
minimal effect on carbohydrates metabolism
–IUCD(Both Cu and LNG-IUD) may be used both
are highly effective and safe in women with
vasculopathy
–Sterilization is considered when family is
completed.

57. Pregestational Diabetes
Female with Diabetes mellitus  conceives
Hyperglycaemia (from day 1 of pregnancy)
Fetotoxic  Congenital malformation in
foetus
Diagnosis of pregestational / overt diabetes
– FBS ≥ 126 mg/dl
– 2 hour PPBS (or) RBS ≥ 200 mg/dl
– HbA1C ≥ 6.5

58. -When a k/c/o diabetes female conceives, risk
of structural anomalies can be predicted by
risk assessment.
-No risk of genetic/ chromosomal anomalous(
Down's syndrome or any aneuploidy)
HbA1C Levels Risks
< 6.5 No risk of congenital
malformations
6.5 3% risk
9 15 – 20% risk

59. RISK REDUCTION
– Tight glucose control : HbA1C < 6.5
– FBS = 70 : 100 mg/dl
– 2 hr PPBS : < 120 mg/dl
– Drug of choice : Insulin
PLANNED PREGNANCY UNPLANNED PREGNANCY
STARTED PRE-
CONCEPTIONALLY
STARTED WHEN
PREGNANCY IS DIAGNOSED

60.  Folic acid supplementation : 400 mcg/day
(same as non diabetic)
 Best investigation to detect congenital
malformation in foetus of diabetic mother-
Anomaly scan (at 18-20 wks  detects
structural abnormalities)
 USG at 11-13 wks  for neural tube
defects assessment

61.  All pregnant females with overt diabetes should
undergo foetal ECHO at 22-24 wks (M/C congenital
malformations involve CVS)
 Pregnant diabetic female has high chances of IUD
& Still birth  To reduce risk  Foetal monitoring
starting from 32 wks of pregnancy

62. MANAGEMENT OF PGDM WITH INSULIN
 Short or rapid acting insulin (e.g. Lispro & Aspart)
are administered before meals to reduce rise in
glucose with food intake.
 Long acting or basal insulins (NPH, Glargine
Detemir) are given to maintain euglycemia between
meals and in the fasting state.
 Usually NPH is used before breakfast with a rapid
acting insulin & prior to the evening meal or at bed
time.

63. OBSTETRIC MANAGEMENT
– No complications, well controlled foetal well being
good 39-40 wks [expectant management
before 40 wks is not recommended]
– Blood Sugar not well controlled & other
complications  Deliver by 37 wks.
– If foetal compromise/ Antenatal complications 
Deliver early  Before 34 wks steroid is given,
higher doses of insulin is added to adjust the
blood sugar level.

64. MANAGEMENT DURING LABOR
 In Planed delivery, at morning, usual bed time
dose of insulin is given.
 Morning dose is withheld or reduced if required
regular insulin (short acting) should be used
instead of long acting insulin, because insulin
requirements typically drops after delivery.
 In labour woman should be hydrated adequately.
Normal saline intravenous drip is started. CBG is
checked hourly using a bedside glucometer.

65.  On the onset of labor after induction or
spontaneous labour if glucose level comes
down below 70 mg%. It is changed to 5% .
Dextrose with 100- 150 ml/hr.
 The goal is to maintain glucose level between
70- 100 mg% above which regular insulin is
given by iv infusion at a rate of 1.25
units/hour.

66. CONGENITAL MALFORMATION IN FETUS
 Incidence is more in overt diabetic mother- 25%
 M/C system involved CVS > CNS
 M/C anomaly overall. VSD > NTD (Neural tube
defect)
 Most specific anomaly overall- Sacral agenesis /
Caudal regression syndrome
 Most specific CVS anomaly – TGA (Transposition of
Great vessels)
 M/C CVS findings – Hypertrophic cardiomyopathy

67. MACROSOMIA
 Defined as fetal weight more than 90th percentile
for that gestational age or estimated Fetal weight
equal to or more than 4000gm.
 Chances of macrosomia increases if mean maternal
blood glucose levels > 130 mg/dl
RISK FACTORS
1. Diabetic mother
2. Male fetuses
3. Obese mothers
4. Post-term pregnancy

68.  Best USG parameter to see macrosomia-
Abdominal circumference of foetus (> 35
cm)
 In foetus  macrosomia if oxygen
requirement is not fulfilled  Episodes of
hypoxia
- Stillbirth/ Sudden IUD occurs. (Maximum in 3rd
trimester)
- Shoulder dystocia occurs.

69. IN MOTHER
1. Protracted or arrested labor
2. Assisted vaginal birth
3. Caesarean section
4. Genital tract lacerations
5. PPH
6. Uterine rupture

70. SHOULDER DYSTOCIA
 Diagnosed when delay in the delivery of shoulder (
> 1 min) after the delivery of head.
 Obstetric emergency.
 “Turtle Sign” – Head of baby recedes back
towards perineum
MANEUVER FOR SHOULDER DYSTOCIA
1. McRobert’s Maneuver
2. Rubin-I Maneuver
3. Rubin-II Maneuver
4. Wood’s Corkscrew Maneuver

71.  Most common foetal complication of
shoulder dystocia – Brachial plexus,
injury leading to Erb’s Palsy.
 Most common maternal complication of
shoulder dystocia - PPH

72. NEONATAL COMPLICATIONS
1. Increased neonatal mortality due to
prematurity & delay of lung maturity.
2. Hypoglycaemia (Blood sugar < 40 mg/dl):
foetus is hypoglycaemic + increased insulin
-As soon as baby is born
-Sources of hyperglycaemia
-Increased insulin leads to hypoglycaemia

73. 3. Hyperbilirubinemia
Due to Hypoxia
Increased erythropoiesis
Increased foetal RBC with short life span
Increased bilirubin

74. 4. Polycythaemia (Due to increased
erythropoiesis) : Hyperbilirubinemia +
Polycythaemia  Hyperviscocity syndrome
5. Hypokalaemia, Hypocalcaemia,
Hypomagnesemia occurs due to prematurity.
6. Usually Anaemia is not seen in baby of diabetic
mother.

75. LONG TERM RISKS OF GDM TO THE MOTHER
1. Increased Dyslipidaemia
2. Increased hypertension
3. Increased abdominal obesity
4. Increased risk of metabolic syndrome
5. Increased recurrence of gestational diabetes
6. Increased risk of development of type-II DM

76. Thank You