Diabetes in Pregnancy

Max Brinsmead MB BS PhDAugust 2016

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 Can obstetric outcomes be changed? These questions answered by the 2005 ACHOIS

study Glucose challenge or GTT

75G one hour test is best for screening IADPSP recommends universal 1-step testing with

75g 2 hr test Criteria for diagnosis Criteria for the use of insulin Role of oral hypoglycaemic drugs

The Effect of Treatment of Gestational Diabetes on Pregnancy Outcomes Crowther et al NEJM June 2005

The ACHOIS study RCT of approx. 1,000 pregnant women with

gestational diabetes; standard care vs blood glucose control by diet +/- insulin

Risk of Perinatal Risk (i.e. death, shoulder dystocia, fracture and N palsy) reduced from 4% to 1%; RR=0.33 (CI 0.14 – 0.75)

Rate of Induction Labour; RR1.36 (CI 1.15 – 1.62) Rate of NICU admissions; RR 1.13 (CI 1.03 – 1.23) No difference in rate of Caesareans Rates of depression and stress in mothers in

the puerperium

Cost Effectiveness of Treatment for Gestational Diabetes Moss et al BMC Preg & Childbirth Oct 2007

From the ACHOIS study For every 100 women with abnormal GTT in

pregnancy (mild gestational diabetes) offered treatment there was $60,000 additional costs From pregnancy multidisciplinary care Induction of labour (10 additional women) Neonatal care admission (9 additional babies)

However saved 1 baby from perinatal death and 2 from neonatal complications Estimated saving $80,000

Hyperglycaemia and Adverse Pregnancy Outcome Study Metzger et al NEJM May 2008

The HAPO study A prospective study of 25,505 women in 19 centres All had a 2-hour 75-g GTT at 24 – 34 weeks Those with Fasting GLUC > 5.7 or 2 hr >11.0 were

identified and removed Remainder followed without knowledge of the GTT

result (a blinded prospective study) Found significant positive associations between

fasting, 1-HR and 2-HR GLUC and LGA babies Primary CS rates Risk of neonatal hypoglycaemia

An RCT of Treatment for Mild Gestational Diabetes Landon et al NEJM October 2009

The MFMU trial 958 women in a number of US centres All had an abnormal 3 Hr GTT but the fasting GLUC

was <5.3 Randomly assigned to treatment or observation Treatment

Reduced mean fetal birthweight by 106g Fewer babies <4 Kg (7.1% vs 14.5% Less shoulder dystocia (1.5% vs 4.0%) Fewer Cesareans (26.9% vs 33.8%) Reduced risk of preeclampsia and gestational hypertension

(8.6% vs 13.6%) All these were significant differences

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 GTT

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

IADPSP criteria Fasting ≥ 5.1 1 hr ≥ 10.0 2 hr ≥ 8.5

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 5.9 – 6.4

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

An RCT of Metformin vs Insulin for Gestational Diabetes Rowan et al NEJM May 2008 From Auckland New Zealand 751 women randomised to Metformin or Insulin 46% of those assigned to Metformin required

supplemental insulin Outcomes the same (Composite RR 0.99 CI 0.80-1.23)

but women preferred Metformin Respiratory distress Prematurity Jaundice Birth Trauma Low Apgar Birthweight Maternal outcomes

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 Best control is with closed-loop insulin pump

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

?role for Betamethasone for the fetal lungs Low threshold for Caesarean especially if

fetal macrosomia is suspect Most gestational diabetics induced at term

i.e. >37 completed weeks but wait for spontaneous or induced Cx ripening

Monitor GLUC in labour May require dextrose and insulin by infusion

for those who are insulin-dependant Monitor the fetus in labour

Any Questions or Comments?

Please leave a note on the Welcome Page to this website