Diabetes in Pregnancyfor Undergraduates

Max Brinsmead MB BS PhD

May 2015

Types and Incidence

KNOWN DIABETIC (Before pregnancy) Insulin dependent – Type 1 or Juvenile Onset

Diabetes NIDM – Type 2 or Maturity Onset Diabetic Together account for <1% of pregnancies

GESTATIONAL DIABETES Diagnosed during a pregnancy May or may not resolve after pregnancy Comprise 2 – 9% of pregnancies depending on the

population

Glucose Metabolism in Pregnancy

Pregnancy is a diabetogenic stress Results from antagonism of insulin by placental

hormones HPL, Sex steroids and corticosteroids

The diabetogenic stress increases as pregnancy advances

But reverses quickly after placenta delivers

BUT… Facilitated transfer of glucose to the parasitic

fetus fasting hypoglycaemia

The Effect of Diabetes on Pregnancy

Maternal blood sugar will Fetal blood sugar and… Fetal insulin

This causes… Fetal growth which Dystocia Caesarean or shoulder difficulties Brachial plexus palsy

BUT Fetal brain growth is reduced Lung maturation is delayed And the neonate is at risk of hypoglycaemia &

hypocalcaemia

Effect of Diabetes on Pregnancy (2)

Fetal blood sugar will cause Fetal glycosuria Polyhydramnios

There is risk of intrauterine death ?due to hypoxia ?due to ketoacidosis

There is Rate of maternal Pre eclampsia ?due to placental bed vasculopathy

There are Risks of Prematurity Some of which is due to intervention on behalf of

the mother

Extra Risks for Type 1 Diabetics

First trimester hyperglycaemia causes… Rates of congenital malformation (CNS & Heart)

If there is diabetic vasculopathy then the inevitable kidney damages causes…

Rates of pre eclampsia Risk of fetal growth retardation

The Effect of Pregnancy on Diabetes

Insulin antagonism Insulin requirements Pregnancy is a state of lipidolysis so IDDM patients

are at risk of ketoacidosis Especially during labour

Will be complicated by nausea, vomiting & slow gastric emptying

And altering energy expenditure A desire for tight glucose control and a parasitic

fetus puts the mother at risk of serious hypoglycaemia

Retinopathy and nephropathy may deteriorate rapidly

Insulin requirements change rapidly after delivery

Principles of Management Family Planning Preconception care Stringent blood glucose control before

pregnancy Monitor HBA1c

Meticulous blood glucose control throughout pregnancy

Multidisciplinary care from Physician, Dietition, Nurse Educator and Obstetrician

Watch for known complications Timely delivery Appropriate mode of delivery Family Planning

Controversies in Gestational Diabetes

Selective or universal testing At least 50% missed unless all screened

Glucose challenge or GTT 75G one hour test is best for screening International Group Physicians recommends

universal 1-step testing with 75g 2 hr test

Criteria for diagnosis Criteria for the use of insulin

Criteria for Selective Testing First degree affected relative Age >35 years Ethnic origin Obesity BMI >30 Poor obstetric history esp. “unexplained

stillbirth” Previous fetal macrosomia (>4.5Kg) Clinical suspicion

Polyhydramnios Macrosomia

Previous Gestational Diabetes

Criteria for the Diagnosis

May begin with Fasting and 2 hr Postprandial GLUC

If Fasting >7.8 or 2 hr PP >11.0 then…

This patient requires insulin ASAP Best test is the WHO 75G 2 hr GTT

Diabetes is Fasting GLUC >5.4 or… 2 hr PP >7.8

Management of Gestational Diabetes

Diet Abstinence from all simple sugars Reduce fats and oils Regular meals with complex CHO (low glycaemic

index)

Exercise Self-tested blood glucose 4x once daily

Aim for Fasting GLUC <5.0 And 2 hr PP <6.5

Metformin or Insulin if targets not met Cease any insulin at delivery Repeat 75g GTT after 8 – 12 weeks

Role for Oral Hypoglycaemics

Use Metformin or Glibenclamide

Achieves the same outcomes as insulin if target GLUC are met

Better than insulin at controlling maternal weight

7 – 46% will go on to require insulin

Management of Insulin Dependent Diabetes

Before Pregnancy Normalise HBa1c Folic acid 5 mg daily Check kidney and retina

Multidisciplinay care Self-tested blood glucose 4x daily

Aim for Fasting GLUC <5.0 And 2 hr PP 5.9 – 6.4

Prenatal diagnosis 1st trimester screening by serum biochemistry + ultrasound Routine morphology at 18w Cardiac ultrasound at 22w

Scan for growth and umbilical Dopplers 28 & 36w

Delivery of the Pregnant Diabetic Timing for Type 1 diabetics is often a juggle

between difficult sugar control and fetal maturity

Low threshold for Caesarean especially if fetal macrosomia is suspect

Most gestational diabetics induced at term i.e. >37 completed weeks

Monitor GLUC in labour May require dextrose and insulin by infusion for

those who are insulin-dependant Monitor the fetus in labour

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