Diabetes in Pregnancy for Undergraduates Max Brinsmead MB

Diabetes in Pregnancy for Undergraduates Max Brinsmead MB BS Ph. D July 2017

Types and Incidence n KNOWN DIABETIC (Before pregnancy) n n Insulin dependent – Type 1 or Juvenile Onset Diabetes NIDM – Type 2 or Maturity Onset Diabetic Together account for <1% of pregnancies GESTATIONAL DIABETES n n n Diagnosed during a pregnancy May or may not resolve after pregnancy Comprise 2 – 9% of pregnancies depending on the population

Glucose Metabolism in Pregnancy n n Pregnancy is a diabetogenic stress Results from antagonism of insulin by placental hormones n n The diabetogenic stress increases as pregnancy advances n n n HPL, Sex steroids and corticosteroids But reverses quickly after placenta delivers BUT… Facilitated transfer of glucose to the parasitic fetus fasting maternal hypoglycaemia

The Effect of Diabetes on Pregnancy n Maternal blood sugar will Fetal blood sugar and… n Fetal insulin n n This causes… Fetal growth which n Dystocia Caesarean or shoulder difficulties n Brachial plexus palsy n n BUT Fetal brain growth is reduced n Lung maturation is delayed n And the neonate is at risk of hypoglycaemia & hypocalcaemia n

Effect of Diabetes on Pregnancy (2) n Fetal blood sugar will cause Fetal glycosuria n Polyhydramnios n n There is risk of intrauterine death ? due to hypoxia n ? due to ketoacidosis n n There is Rate of maternal Pre eclampsia n n ? due to placental bed vasculopathy There are Risks of Prematurity n Some of which is due to intervention on behalf of the mother

Extra Risks for Type 1 Diabetics n First trimester hyperglycaemia causes… n n Rates of congenital malformation (CNS & Heart) If there is diabetic vasculopathy then the inevitable kidney damages causes… Rates of pre eclampsia n Risk of fetal growth retardation n

The Effect of Pregnancy on Diabetes n n Insulin antagonism Insulin requirements Pregnancy is a state of lipidolysis so IDDM patients are at risk of ketoacidosis n n n 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 n n n Family Planning Preconception care Stringent blood glucose control before pregnancy n n Meticulous blood glucose control throughout pregnancy n n n Monitor HBA 1 c 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 n Selective or universal testing n n At least 50% missed unless all screened Glucose challenge or GTT 75 G one hour test is best for screening n International Group Physicians recommends universal 1 -step testing with 75 g 2 hr test n n n Criteria for diagnosis Criteria for the use of insulin

Criteria for Selective Testing n n n n First degree affected relative Age >35 years Ethnic origin Obesity BMI >30 Poor obstetric history esp. “unexplained stillbirth” Previous fetal macrosomia (>4. 5 Kg) Clinical suspicion Polyhydramnios n Macrosomia n n Previous Gestational Diabetes

Criteria for the Diagnosis n May begin with Fasting and 2 hr Postprandial GLUC If Fasting >7. 8 or n 2 hr PP >11. 0 then… n n Test for ketonaemia This patient requires insulin ASAP Best test is the WHO 75 G 2 hr GTT Diabetes is Fasting GLUC >5. 4 or… n 2 hr glucose is >7. 8 n

Management of Gestational Diabetes n Diet Abstinence from all simple sugars n Reduce fats and oils n Regular meals with complex CHO (low glycaemic index) n n n Exercise Self-tested blood glucose 4 x once daily Aim for Fasting GLUC <5. 0 (<5. 3 NICE) n And 2 hr PP <6. 4 (1 hr <7. 8) n n Metformin or Insulin if targets not met Cease any insulin at delivery Repeat 75 g GTT after 8 – 12 weeks

Role for Oral Hypoglycaemics n Use Metformin or Glibenclamide n Achieves the same outcomes as insulin if target GLUC are met n Better than insulin at controlling maternal weight n 7 – 46% will go on to require insulin

Management of Insulin Dependent Diabetes n Before Pregnancy n n n Multidisciplinay care Self-tested blood glucose 4 x daily n n n Aim for Fasting GLUC <5. 0 but >4. 0 And 2 hr PP 5. 6 – 6. 4 Prenatal diagnosis n n Normalise HBa 1 c Folic acid 5 mg daily Check kidney and retina 1 st trimester screening by serum biochemistry + ultrasound Routine morphology at 18 w Cardiac ultrasound at 22 w Scan for growth and umbilical Dopplers n 28 & 36 w

Delivery of the Pregnant Diabetic n Timing for Type 1 diabetics is often a juggle between difficult sugar control and fetal maturity n Low threshold for Caesarean especially if fetal macrosomia is suspect n Most gestational diabetics induced at term i. e. >37 completed weeks n Monitor GLUC in labour n n May require dextrose and insulin by infusion for those who are insulin-dependant Monitor the fetus in labour

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