This document provides information on gestational diabetes mellitus (GDM), including its definition, causes, physiological changes during pregnancy that can lead to GDM, effects on pregnancy, fetal and neonatal hazards, diagnosis, screening recommendations, treatment including medical nutrition therapy and insulin management, monitoring during labor and delivery, and postpartum care considerations. GDM is defined as glucose intolerance that begins or is first recognized during pregnancy and results from changes in insulin resistance and secretion during pregnancy. Left untreated, GDM can increase risks for the mother and fetus, so proper screening, diagnosis, and treatment are important aspects of prenatal care.

1. GESTATIONAL
DIABETES MELLITUS
Dr.PolyBegum
AssistantProfessor(Obst&Gynae)
DAMC,Faridpur

2. DEFINITION & MAGNITUDE
GDM is defined as carbohydrate intolerance of
variable severity with onset or first recognition
during the present pregnancy.
Not the same as Type 1 or Type 2 Diabetes
Varies worldwide & among different racial
and ethnic groups within a country

3. ETIOLOGY
 Pregnancy  pre-diabetic state
 Pregnancy  marked insulin resistance  increased insulin
requirement  GDM
 Complicates 4% of all pregnancies
 60% to 80 % of women with GDM are obese & experience
insulin resistance & GDM

4. PHYSIOLOGICAL CHANGES
4
During pregnancy, there is a state
called DIABETOGENIC STATE, peak @
28-32w
Due to ↑ hormone produced by placenta :
HPL, CORTISOL (insulin antagonist) →
relative insulin resistance
Glucose crosses the placenta by facilitated
diffusion & fetal blood glucose level closely
follow the maternal level

5. Fasting and & postprandial
venous plasma sugar
during pregnancy
Fasting
2h
postprandial Result
<100 mg/dl < 145mg/ dl Not diabetic
>125 mg/ dl >200 mg/ dl Diabetic
100-125 mg/dl 125-200 mg/dl
Border line indicates
glucose tolerance test

6. Pregnancy Pathophysiology
 Glucose is a teratogen at high levels
 Crosses placenta readily while insulin cannot
 Insulin resistance occurs because hormonal
changes associated with pregnancy partially
block the effects of insulin
 Insulin resistance causes glucose to be
shunted from mother to the fetus to facilitate
fetal growth and development

7.  Subsequent increase in insulin resistance causes
maternal glucose levels to increase 80% of non-pregnant
women
Increased insulin resistance
Decreased insulin secretion
Increased maternal glucose
GDM
 GDM disappears after pregnancy
 Useful physiologic process out of balance

8. Effects of diabetes on pregnancy
 Abortion
 Preterm labour
 Infection
 Increase incidence of pre-eclampsia
 Polyhydramnios
 Maternal distress
 Diabetic retinopathy
 Diabetic nephropathy
 Diabetic ketoacidosis.
 Shoulder dystosia
 Prolong labour
 PPH
 Puerperal sepsis

9. Fetal and Neonatal Hazards
A) Fetal:
 Fetal macrosomia
 Congenital malformation
 Birth injury
 Growth restriction
 Fetal death
B) Neonatal:
 Hypoglycemia
 Respiratory distress syndrome
 Hyperbilirubinemia
 Polycythemia
 Hypocalcaemia
 Hypomagnesaemia

10. GESTATIONAL DIABETES DIET
 Water foods are the main concentration. That
means plants: vegetables, fruits, grains &
legumes
 Only low-fat and non-fat dairy products
 Avoid saturated fats
 Avoid fast foods, processed foods, microwave
foods, high-sugar foods, alcohol & high-sodium
foods
 Drink plenty of fresh water every day
 Eat 5 or 6 small meals everyday
 Eat your meals at the same times every day

11. GESTATIONAL DIABETES Diet
 Diet- 30 kcal/kg – normal weight
women, 24 Kcal/kg for overweight
women, and 12 Kcal/kg for
morbidly obese women.
 Diet should contain carbohydrate
50%, protein 20% and fat 25-30%.
Usually three meal regimen, with
breakfast 25% of the total intake,
lunch 30%, dinner 30%.

12. DIAGNOSIS
 TWO-STEP STRAREGY
 50g oral glucose challenge
 Single serum glucose measurement @ 1 hr
 <7.8 mmol/L(<140mg/dL)  normal
 >7.8 mmol/L(>140mg/dL)
 100-g oral glucose challenge
 Serum glucose measurements in fasting state, I, II & III hrs
 Normal values
 Fasting  < 5.8 mmol/L (<105mg/dL)
 I hr  < 10.5 mmol/L (<190mg/dL )
 II hr  < 9.1 mmol/L (<165mg/dL)
 III hr  < 8.0 mmol/L (<145mg/dL)

13.  Overnight fast of at least 8 hours
 At least 3 days of unrestricted diet and unlimited
physical activity
 > 2 values must be abnormal
 Urine glucose monitoring is not useful in
gestational diabetes mellitus
 Urine ketone monitoring may be useful in
detecting insufficient caloric or carbohydrate
intake in women treated with calorie restriction

15. SCREENING
 Essentially all Indian women have to be screened
for gestational diabetes mellitus as they belong
to a high risk ethnicity
 LOW RISK GROUPS:
 <25 yrs of age
 BMI <25kg/sq.m
 No H/O maternal macrosomia
 No H/O diabetes
 No H/O D.M in first degree relative
 Not members of high risk ethnic groups
 Member of an ethnic group with a low prevalence
of GDM
 No H/O abnormal glucose tolerance
 No H/O poor obstetric outcome

16.  INTERMEDIATE RISK
 At least one of the criteria in the list
 HIGH RISK
 Marked obesity
 Prior GDM
 Glycosuria
 Strong family history
 Must be done between 24 & 28 weeks of
pregnancy
 Most GDM cases revert to normal after delivery

17. Value of Screening During
Current Pregnancy
 Increased screening, identification and treatment
can decrease the morbidity and mortality of GDM
 Decreased macrosomia, cesarean birth and birth
trauma due to a > 4000g infant
 Decreased neonatal hypoglycemia,
hypocalcaemia, hyperbilirubinemia,
polycythaemia
 Identify women at future risk for diabetes and
those with insulin resistance

18.  Women are generally screened for GDM with
glucose challenge test in the late second
trimester
 If result is abnormal  oral glucose tolerance
test
 Abnormal glucose challenge test but no GDM
increased risk of future cardiovascular disease
 They have a lower risk than women who actually
did have gestational diabetes

19.  RETESTING
Negative initial test but risk factors
present
Obesity
>33 years of age
Positive 1 hour screen followed by a
negative OGGT
3+/4+ glucosuria
 Low risk  no screening
 Average risk  at 24-28 weeks
 High risk  as soon as possible

20. Treatment
 The total first dose of insulin is calculated according to the
patient’s weight as follow
 In the first trimester  weight x 0.7
 In the second trimester  weight x 0.8
 In the third trimester  weight x 0.9

21. Medical nutrition therapy
 Approximately 30 kcal/kg of ideal
body weight
 >40-45% should be carbohydrates
 6-7 meals daily( 3meals, 3-4 snacks)
 Bed time snack to prevent ketosis
 Calories guided by fetal well
being/maternal weight gain/blood
sugars/ ketones
 Energy requirements during the first 6
months of lactation require an
additional 200 calories above the
pregnancy meal plan

22. Fetal monitoring
 Baseline ultrasound :
fetal size
 At 18-22 weeks 
major malformations &
fetal echocardiogram
 26 weeks onwards 
growth and liquor
volume
 III trimester  frequent
USG for accelerated
growth (abdominal:
head circumference)

23. Insulin Management during Labour &
Delivery
 Usual dose of intermediate-acting insulin
is given at bedtime
 Morning dose of insulin is withheld
 I.V infusion of normal saline is begun
 Once active labor begins or glucose
levels fall below 70 mg/dl, infusion is
changed from saline to 5% dextrose &
 delivered at a rate of 2.5 mg/kg/min
 Glucose levels are checked hourly using
a portable meter allowing for adjustment
in infusion rate
 Regular (short-acting) insulin is
administered by iv infusion if glucose
levels exceed 140 mg/dl

24.  Maternal hyperglycemia in labor: fetal hyperinsulinaemia,
worsen fetal acidosis
 Maintain sugars: 80-120 mg/dl (capillary70-110mg/dl )
 Feed patient the routine GDM diet
 Maintain basal glucose requirements
 Monitor sugars 1-4 hrly intervals during labour
 Give insulin only if sugars more than 120 mg/dl
 Maternal complication
 Fetal complication
 Glycemic monitoring: SMBG and targets
 Fetal monitoring: ultrasound
 Planning on delivery
 Long term risks

25. Mode of delivery
 NVD or Caesarean delivery
Indication of C/S
 Elderly primi gravidae
 Multi-gravidae with BOH
 Diabetes with complications or difficult to
controls
 Obstetrics complications –
Polyhydramnios, PE, Mal-presentation
 Fetal macrosomia

26. Puerperium
 Antibiotics
 Insulin
 Blood glucose monitoring
 Breast Feeding
 Care of baby

27. Contraception
 Barrier method
 Low dose combined oral pill
 IUCD (?)
 Permanent sterilization

28. THANK YOU