Diabetes in pregnancy

1. Diabetes in pregnancy

2. Why? • Paradigm of medical diseases in pregnancy • Effect of pregnancy on disease • Short-term • Long-term • Effect of disease on pregnancy • Mother vs. fetus • Disease vs. its treatment • Prepregnancy vs. gestational

3. Prepregnancy diabetes • Approximate prevalence 0.5% • Increasing • In Australia 75% type 1, 25% type 2 • Varies with ethnic mix

4. Effect of pregnancy on diabetesShort-term • Pregnancy is diabetogenic • HPL, progesterone antagonize insulin • Glucose is major energy substrate for fetus • Pregnancy causes insulin resistance

5. Insulin requirements in pregnancy

6. Effect of pregnancy on diabetesLong-term effects • Nephropathy • None if mild-moderate • If severe (creatinine > 0.25 mmol/L), may exacerbate renal failure • Retinopathy • Seems to make it worse, but probably due to tight control (DCCT)

7. Effects of diabetes on pregnancy • Treatment • OHAs rarely used • Sulphonylureas ?teratogenic • Troglitazone hepatotoxic • Acarbose not effective, side effects • Metformin ok, but rarely adequate • Insulin • Only problem if too much or not enough!

8. Maternal complications of diabetes • Miscarriage • Polyhydramnios • Preeclampsia (more if diabetic nephropathy) • Infection (UTI, candidiasis, chorioamnionitis) • Operative delivery (CS rate 50%) • PPH

9. Fetal complications of diabetes • Miscarriage • Congenital Malformations • 2 - 3 times background rate • minimized by good control around the time or conception and organogenesis • commonest are neural tube and cardiac defects • Caudal regression (sacral agenesis) rare • Perinatal Death • Late “unexpected” FDIU • perinatal mortality rate doubled

10. Neonatal effects of maternal diabetes (IDM) • Macrosomia (40%) • Birth trauma • Hypoglycaemia • Hypocalcaemia/magnesaemia • Respiratory distress syndrome • Hypertrophic Obstructive CardioMyopathy (HOCM) • Hyperbilirubinaemia • Hyperviscosity/ polycythaemia • The risk of type 1 diabetes mellitus in the child of a woman with the condition is 2%.

11. Prepregnancy counselling • Education about diabetes and pregnancy • Investigation for complications of diabetes • Microalbuminuria, ophthalmoscopy • Optimize glycaemic control • Excellent control minimizes congenital anomalies • Switch OHA to insulin • HbA1c • Importance of fetal surveillance • Lifestyle disruption • Folic acid • Rubella

12. Management in pregnancy • TEAM APPROACH • Unified clinic • Obstetrician, endocrinologist, diabetes educator, dietitian, neonatal paediatrician (itfot) • Increased frequency of visits • 4-weekly to 20 weeks • 2-weekly to 28 weeks • Weekly thereafter

13. First visit • Routine management PLUS • Repeat prepregnancy counselling steps • Urinary protein/ microalbumin excretion • Ophthalmoscopy each trimester • Glycaemic control • Organize fetal surveillance

14. Glycaemic control • Home blood glucose monitoring qid • Goals are 5.5 mmol/L fasting and 7 mmol/L 2 hours postprandial • HbA1c monthly • Dietary management • Appropriate energy intake • 50-60% CHO, 25% fat, 15% protein • Even distribution • Exercise - 30 minutes walk a day • Insulin • Basal-bolus: 1 dose medium-long acting insulin (e.g. isophane), short-acting with each meal • Hypo management

15. Fetal surveillance • Ultrasound • 12 weeks • gross morphology, dates, plurality, nuchal translucency • 18-20 weeks • detailed morphology • 30 and 34 weeks • growth • Other scans, Dopplers as indicated • Prevention of FDIU • CTG weekly from 30 weeks, 2/week from 36 weeks

16. Timing and route of delivery • RCT suggests advantage in delivery at 38 - 39 weeks • Decreased macrosomia, shoulder dystocia • 40 weeks if perfect control, no complications • ?Role of elective CS for macrosomia • Diabetes is independent risk factor for shoulder dystocia • Recommend if estimated fetal weight > 4.5 kg • Consider if EFW 4 - 4.5 kg

17. Management in labour1. Glycaemic control • Notify endocrinologist • Omit morning insulin the day of induction. • Measure blood glucose on admission and every 2 hours. • 50 U insulin in 50 mL 0.9% NaCl (1U/mL) via syringe pump • Start at 1mL/hour • Adjust to keep glucose 4-7 mmol/L • Simultaneous 5% dextrose at 100 mL/hour

18. Management in labour2. Obstetric considerations • Usual obstetric management PLUS • Continuous CTG • Epidural analgesia is encouraged • End should be in sight in 12 hours • 2nd Stage - Anticipate Shoulder Dystocia • Experienced accouchouer and paediatrician must be present. • Prepare to re-position patient (over edge of bed and exaggerated lithotomy) • Active Management of 3rd Stage • If elective CS, do first on list

19. Puerperium • Cease insulin infusion at delivery (unless Caesarean section) • Often reduced needs for 24 hours • Then back to prepregnancy dose • Type 2 may need no treatment in puerperium • OHAs discouraged in lactation

20. Gestational Diabetes

21. What is gestational diabetes? • Carbohydrate intolerance of varying severity first manifest or diagnosed in pregnancy • The definition applies irrespective of the need for insulin treatment and the result of any postnatal glucose tolerance test

22. Why gestational diabetes? • Was noted that women with diabetes in pregnancy had high perinatal mortality rate without treatment • This sometimes preceded recognition of diabetes • Pregnancies also characterized by fetal macrosomia • Pregnancy is diabetogenic

23. Hypothesis • Pregnancy can induce a temporary hyperglycaemic state in susceptible women • This can lead to the typical sequelae of diabetes in pregnancy • Macrosomia, preeclampsia, perinatal mortality • Recognition and treatment of these women can avert these problems • Marker for later development of diabetes mellitus

24. Diagnosis • Test of carbohydrate metabolism at 24 - 28 weeks in all pregnant women • Earlier if high-risk, esp. previous GDM • Most convenient is glucose tolerance test • Fasting glucose, 75 g load, 2-hour glucose • GDM = fasting  5.5 mmol/L OR 2-hour  8.0 mmol/L • Sometimes preceded by glucose challenge test • Non-fasting 75 g glucose load, 1-hour blood glucose • Positive test  8.0 mmol/L leads to GTT

25. Treatment • Some individual variation, but 3 key elements 1. Achieve normoglycaemia 2. Monitor fetal well-being 3. Appropriate timing of delivery

26. Achieve normoglycaemia • Monitor blood glucose • Aim for fasting < 5.5 mmol/L and 2-hour postprandial < 6.5 - 7 mmol/L • Initiate carbohydrate modified diet with balanced intake during day • Exercise - 30 minutes walk per day • Insulin as required in 25% • Usually 1-2 doses per day sufficient

27. Ensure fetal well-being • Timing of investigations variable • Most perform some test in late pregnancy • Commonest test is CTG • Start 30 - 36 weeks depending on other features • Ultrasound to determine fetal size

28. Timing of delivery • If well-controlled, not on insulin, no other problems, deliver at term • Recommend elective Caesarean section if estimated fetal weight > 4.5 kg • Consider if EFW 4 - 4.5 kg • If suspected macrosomia, poor control, deliver at 38 weeks

29. Management in labour • If not on insulin, usual management + 4-hourly blood glucose • Notify if > 7mmol/L • If on low-dose insulin (< 20 U/day) may not need any • If on higher-dose insulin, insulin and glucose infusions as for prepregnancy diabetes • 50 U insulin in 50 mL 0.9% NaCl • Start at 1mL/hour • Adjust to keep glucose 4-7 mmol/L • Simultaneous 5% dextrose at 100 mL/hour

30. Management at delivery • Prepare for shoulder dystocia • Cease insulin if used at delivery • Monitor infant’s blood glucose after delivery • Measure mother’s blood glucose BD for 2 days

31. Long-term management • Recall at 6 weeks postpartum for GTT • 2% will have diabetes • 10% will have IGT • Long-term risk of diabetes mellitus 50% over 10 years • Long-term follow-up • Lifestyle modification • 50% recurrence in future pregnancy