Gestational Diabetes Mellitus

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Gestational Diabetes Mellitus

• Dr. R V S N Sarma., M.D., M.Sc., (Canada)
• Consultant Physician Chest Specialist
• Visit us at www.drsarma.in

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Gestational Diabetes Mellitus

• Is it physiological?
• Is it a disease?
• Should we screen for gdm?
• Does it require treatment?
• Recent RCTs settled the issues

Crowther et al. NEJM 2005352
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Glucose Intolerance in Pregnancy
Prevalence of GDM 3 to 18
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GDM - Definition

• Distinguish GDM from Pre-gestational DM
• Abnormal Glucose Tolerance
• Onset (begins) with pregnancy or
• Detected first time during pregnancy
• No h/o of pre pregnancy DM or IGT
• Hb A 1 c is usually lt 7.5 in GDM
• In DM Pregnancy it is gt 7.5
• GDM is a forerunner of T2DM

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Pathogenesis of GDM

• Pregnancy is Diabetogenic condition
• A Wonderful Metabolic Stress Test
• Placental Diabetogenic Hormones
• Progesterone, Cortisol, GH
• Human Placental Lactogen (HPL), Prolactin
• Insulin Resistance (IR), ? ? cell stimulation
• Reduced Insulin Sensitivity up to 80
• Impaired 1st phase insulin, Hyperinsulinemia
• Islet cell auto antibodies (2 to 25 cases)
• Glucokinase mutation in 5 of cases

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Fundamental Defect in GDM

• The hormones of pregnancy cause IR
• They also cause direct hyperglycemia
• But, the basic defect is
• The maternal pancreatic ? cells are unable to
  compensate for this increased demand

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Normal Glucose Tolerance
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Abnormal GT in GDM
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Risk Stratification for GDM

• High Risk Group (Indians mostly)
• BMI ? 30 PCOD Age gt 35 years
• F h/o DM Ethnic predisposition Acanthosis
• Previous h/o GDM, IGT, Macrosomic baby
• Low Risk Group
• Age lt 25, BMI lt 23, No F h/o DM or IGT
• No bad obstetric history No ? risk ethnicity
• Intermediate Risk Group
• Not falling in the above two classes

Adopted from ADA guidelines
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Whom to Screen for GDM ?

• Low Risk Group
• No screening required for GDM
• Intermediate Risk Group
• Screen around 2428 weeks of gestation
• High Risk Group
• As soon as possible after conception
• Must - before 2428 weeks of gestation
• Better do a full 3 hr OGTT for GDM
• If negative screening in 2nd 3rd trimester

Adopted from ADA guidelines
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Indian Scenario

• Since the pregnant mothers without any of the
  risk factors are so very few in India
• Since we boast of being in the DM capitol
• We need to screen all pregnant women
• And identify early the GDM problem
• We have enough tough maternal problems
• Let us at least treat a treatable problem

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GDM Two Step Screening

• Two Step Screening
• Do a Random Glucose Challenge Test (GCT)
• 50 grams of oral glucose any time of day
• 1 hour post test for plasma glucose (1 hr PG)
• Result gt 180 mg - Dx of GDM confirmed
• Result gt 140 mg - Dx of GDM suspected
• 140 to 180 We need OGTT (100 g) to confirm
• One Step Screening
• OGTT 3 hours after 100 g of oral glucose

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Glucose Challenge Test (GCT)
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Please be specific

• Do not use the loose word Blood Sugar
• Be specific to measure Plasma Glucose
• Always venous sample for OGTT
• No capillary blood testing for OGTT
• NaF to be added as anticoagulant to blood
• Centrifuge to separate plasma immediately
• Plasma glucose to be estimated a.s.a.p
• Glucometer can be used for monitoring

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OGTT 100g 3 hour Test
Test sample timing Plasma Glucose value
Fasting (mg) 95
1 hour (mg) 180
2 hour (mg) 155
3 hour (mg) 140
One abnormal Value is enough
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Some Questions

• When to order for USG ?
• Scan for anomalies at 20-weeks
• Growth scans from 26-28 weeks
• Breast feed or not after delivery ?
• Must give breast feeding
• This reduces maternal glucose intolerance

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GDM Fetal Morbidity

• Macrosomia of the baby
• CPD Shoulder Dystocia
• Intrapartum Trauma Feto-maternal
• Congenital Anomalies, HCM
• Neonatal Hypoglycemia
• Neonatal Hypocalcemia
• Neonatal Hyperbilirubinemia
• Respiratory Distress Syndrome (RDS)
• Polycythemia (secondary) in the new born

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Macrosomia

• Birth weight gt 4000 g - 90th percentile GA
• ? Intrapartum feto-maternal trauma
• Increased need for C- Section
• 20 30 of infants of GDM Macrosomic
• Maternal factors for Macrosomia
• Uncontrolled Hyperglycemia
• Particularly postprandial hyperglycemia
• High BMI of mother
• Older maternal age, Multiparity

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Macrosomic Newborn (4.2kg)
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Shoulder Dystocia
Erbs palsy
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Macrosomia
GDM Non DM P value
Birth Weight 3512 g 3333 g lt 0.05
LGA 40.4 13.7 lt 0.001
Macrosomia 32.0 11.0 lt 0.01
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Neonatal Hypoglycemia

• Due to fetal hyperinsulinemia
• Neonatal plasma glucose lt 30 mg
• Poor glycemic control before delivery
• Increases perinatal morbidity
• Congenital anomalies 3 to 8 times more
• More if periconception hyperglycemia
• Assoc. maternal fasting hyperglycemia

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Minor Adverse Health Effects
Normal GDM DM P
Birth Wt (g) 330364 364951 384972
lt0.01 Macrosomia() 8 36 47 lt0.01 C-S
5 10 14 lt0.01 Hypoglycemia
2 28 52 lt0.01 Hypocalcemia 0 4
7 lt0.01 Hyperbilirubinemia 15 23 21 lt0.01 Polycy
themia 0 7 11 lt0.01 Cord C-Pep 1.180.1
2.070.12 2.980.22 lt0.01 Cord Glu 1003.6
1032.9 1145.5 lt0.01
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Major Adverse Health Effects
Normal DM
CNS 6.4 18.4 Congenital heart
disease 7.5 21.0 Respiratory
disease 2.9 7.9 Intestinal
atresia 0.6 2.6 Anal atresia 1.0 2.6
Renal Urinary defect 3.1 11.8 Upper limb
deficiencies 2.3 3.9 Lower limb
deficiencies 1.2 6.6 Upper Lower
spine 0.1 6.6 Caudal digenesis 0.1 5.3
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Neonatal Complications
DM GDM Normal p-value
T. hypoglycemia() 52 28 3 lt0.01 P.
hypoglycemia() 6 2
0 lt0.01 Hypocalcemia() 5 5
0 lt0.01 Hyperbilirubinemia()
21 23 15 lt0.01 Trans tachypnea() 5 2
0 lt0.01 Polycythemia() 11 7
0 lt0.01 RDS() 5 2
0 lt0.01IUGR() 2 1 0 lt0.05
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Congenital Anomalies - DM Control

• Maternal HbA1c levels
• lt 7.2 Nil
• 7.2-9.1 14
• 9.2-11.1 23
• gt 11.2 25
• Critical periods - 3-6 weeks post conception
• Need pre-conceptional metabolic care

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Late effects on the offspring

• Increased risk of IGT
• Future risk of T2DM
• Risk of Obesity

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Maternal Morbidity

• Hypertension Insulin Resistance
• Preeclampsia and Eclampsia
• Cesarean delivery Pre term labour
• Polyhydramnios fluid gt 2000 ml
• Post-partum uterine atony
• Abruptio placenta

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Risk of T2DM after GDM

• IGT and T2DM after delivery in 40 of GDM
• R.R of T2DM for all with GDM is 6 (C.I. 4.1
  8.8)
• Must be counseled for healthy life style
• Re-evaluate with 75 g OGTT after 6 wk, 6 months
• More risk - if GDM before 24 wks of gestation
• High levels of hyperglycemia during pregnancy
• If the mother is obese and has ve family h/o
• GDM in previous pregnancies and age gt 35 yrs.
• High risk ethnic group (like Indians)

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A Delicate Balance !

• Plasma Glucose values in pregnancy
• hang on a delicate balance
• If the Mean Plasma Glucose (MPG) is
• Less than 87 mg - IUGR of fetus
• More than 104 mg - LGA of fetus
• It is imp. to screen for hypothyroidism

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Women with T2DM

• T2DM patients must plan their pregnancy
• Preconception Hb A1c ? 7.00 MAU estimate
• OADs should be discontinued Folic acid
• Start on Insulin and titrate for euglycemia
• Nutrition and weight gain counseling
• ACEi and ARB must be substituted
• Screening for retinopathy nephro (eGFR lt90)
• Must avoid hypoglycemia and ketosis
• SMBG must be trained and started

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GDM Glycemic Targets
Recommended values for Glycemic Targets
Pre-pregnancy Hb A1c ? 7.00 (if possible ? 6.00)
Pregnancy values Range
FPG 70 - 95
1 hr PPG 100 140
2 hr PPG 90 120
Hb A1c ? 6.00
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GDM and MNT

• Two weeks trial of Medical Nutrition Therapy
• Pre-pregnancy BMI is a predictor of the efficacy
• If target glycemia is not achieved initiate
  insulin
• MNT extra 300 calories in 2 and 3rd trimesters
• Calories 30 kcal/kg/day 1800 kcal for 60 kg
• If BMI gt 30 then only 25 kcal/kg/day
• 3 meals and 3 snacks avoid hypoglycemia
• 50 of total calories as CHO, 25 protein fat
• Low glycemic, complex CHO, fiber rich foods

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Diet therapy in GDM

• Small, frequent meals
• Avoid eating for two
• Avoid fasts and feasts
• Avoid health drinks
• Eat a bedtime snack

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Tips for diet management

• Small breakfast
• Mid morning snack
• High protein lunch
• Mid afternoon snack
• Usual dinner
• Bed time snack

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GDM and Exercise

• Recumbent bicycle
• Upper body egometric exercises
• Moderate exercises
• Mother to palpate for uterine contractions
• Walking is the simplest and easiest
• Continue pre pregnancy activity
• Do not start new vigorous exercise

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GDM and Insulins

• In 10 to 15 of GDM, MNT fails Start on insulin
• Good glycemic control No increased risk
• Human Insulins only Not Analogs
• Daily SMBG up to 7 times!
• Insulin Glargine (Lantus) Not to be used at all
• Insulin Lispro tested and does not cross placenta
• Insulin Aspart not evaluated for safty
• CSII may be needed in some cases
• Oral drugs not recommended (SU?, Metformin?)

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Insulin Regimen

• If MNT fails after 2 - 4 weeks of trial
• Initiate Insulin Continue MNT
• Dose 0.7, 0.8 and 0.9 u/kg 1, 2 3 trim.
• Eg. 1st trim 64 kg 0.7 x 64 45 units
• Give 2/3 before BF 30 units of 3070 mix
• Give 1/3 before supper 15 u of 5050 mix
• Increase total dose by 2-4 units based on BG
• After BG levels stabilize monitor till term

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GDM and Delivery

• Delivery until 40 weeks is not recommended
• Delivery before 39th week assess the pulmonary
  maturity by phosphatase test on amniocentesis
  fluid
• C - Section may be needed (25 -30)
• Be prepared for the neonatal complications
• Assess the mother after delivery for glycemia
• May need to continue insulin for a few days
• Pre-gestational DMInsulin (30 less) or OAD

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punarapi jananam punarapi maranam Once again is
the birth, sure follows the death punarapi
jananee jaTarae sayanam Yet again, is the
slumber in the uterine filth iha samsaarae bahu
dustaarae he! what to say of this miserable
troth kripayaa paarae paahi muraarae O! lord,
save us from this cyclical myth
Jagad Guru Adi Sankaracharyas Bhaja Govindam
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Punarapi GarbhamYet another conception
Punarapi Prasavam Yet another child-birth
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Punarapi JananeeOnce again for the mom
Sisuvau KaTinam and the babe, the miseries
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Iha Madhu maehaeThis Diabetes you see
Bahu Dustarae Terrible to the core
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Kripaya NivaaarePlease put an end to this
Nipunarae vidyae O! Doctor, the expert !
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Punarapi Jananam