Obstetrics - DM in pregnancy

Question 1

Diabetes Mellitus in Pregnancy

Answer 1

• Metabolic condition in which patient has hyperglycaemia
• Due to insulin sensitivity
• Or decreased insulin secretion

Question 2

Diabetes Mellitus in Pregnancy

Causes?

Answer 2

• Pre-existing
• Gestational

Question 3

Diabetes Mellitus in Pregnancy

Causes?

Pre-existing?

Answer 3

Type 1 DM:

• Autoimmune - destruction of panccreatic beta cells - no insulin
• Juvenile onset
• Associated with HLA-DR3/HLA-DR4
• Patients at risk of ketoacidosis

Type 2 DM

• Patients become gradually insulin resistant or pancreatic cells fail to secrete insulin or both
• Incidence increasing in younger population
• Patients at risk of developing hyperosmolar state
• Dehydration
• Osmolality >320mosmol/kg
• Hyperglycaemia >30 mmol/L with pH >7.3, bicarbonate >15mmolL and no significant ketonenaemia <3mmol/L
• Chronic pancreatitis - destroys both alpha and beta pancreatic cells so glucagon and insulin no longer produced

Question 4

Diabetes Mellitus in Pregnancy

Causes?

Gestational?

Answer 4

Risk factors for gestational diabetes

• BMI of > 30 kg/m²
• previous macrosomic baby weighing 4.5 kg or above
• previous gestational diabetes
• first-degree relative with diabetes
• family origin with a high prevalence of diabetes (South Asian, black Caribbean and Middle Eastern)

Question 5

Diabetes Mellitus in Pregnancy

Symptoms?

Answer 5

• General: polyuria, polyphagia (xs appetite), polydipsia (xs thirst), blurred vision, glycosuria (xs sugar in urine)
• Microvascular (coronary artery disease, peripheral arterial disease, and stroke) maccrovascular changes
• More common in type 1 DM:
  
  • acetone breath
  • weight loss
  • Kussmaul breathing
  • Nausea and vomitting

Question 6

Diabetes Mellitus in Pregnancy

Screening for gestational diabetes?

Answer 6

Screening for gestational diabetes

• women who’ve previously had gestational diabetes: oral glucose tolerance test (OGTT) should be performed as soon as possible after booking and at 24-28 weeks if the first test is normal.
• NICE also recommend that early self-monitoring of blood glucose is an alternative to the OGTTs
• women with any of the other risk factors should be offered an OGTT at 24-28 weeks

Question 7

Diabetes Mellitus in Pregnancy

Diagnostic Thresholds for gestational DM

Answer 7

Diagnostic thresholds for gestational diabetes:

• these have recently been updated by NICE, gestational diabetes is diagnosed if either:
• fasting glucose is >= 5.6 mmol/l
• 2-hour glucose is >= 7.8 mmol/l

Specific to gestational DM

• Oral glucose tolerance test at 16-18 weeks and 28 weeks if initial test is normal
• Gestational Diabetes maybe diagnosed - blood glucose is>9mmol/L 2 hours after 75g glucose loading

Question 8

Diabetes Mellitus in Pregnancy

Management of Gestational DM

Answer 8

Management of gestational diabetes:

• newly diagnosed women should be seen in a joint diabetes and antenatal clinic within a week
• women should be taught about selfmonitoring of blood glucose
• advice about diet (including eating foods with a low glycaemic index) and exercise should be given
• if the fasting plasma glucose level is < 7 mmol//l a trial of diet and exercise should be offered
• if glucose targets are not met within 1-2 weeks of altering diet/exercise metformin should be started
• if glucose targets are still not met insulin should be added to diet/exercise/metformin
• if at the time of diagnosis the fasting glucose level is >= 7 mmol/l insulin should be started
• if the plasma glucose level is between 6-6.9 mmol/l, and there is evidence of complications such as macrosomia or hydramnios (xs amniotic fluid accumulation), insulin should be offered
• glibenclamide should only be offered for women who cannot tolerate metformin or those who fail to meet the glucose targets with metformin but decline insulin treatment

Question 9

Diabetes Mellitus in Pregnancy

Management of pre-existing diabetes

Answer 9

Management of pre-existing diabetes:

• weight loss for women with BMI of > 27 kg/m^2
• stop oral hypoglycaemic agents, apart from metformin, and commence insulin
• folic acid 5 mg/day from pre-conception to 12 weeks gestation
• detailed anomaly scan at 20 weeks including four-chamber view of the heart and outflow tracts
• tight glycaemic control reduces complication rates
• treat retinopathy as can worsen during pregnancy

Question 10

Diabetes Mellitus in Pregnancy

Targets for self monitoring of pregnant women (pre-existing and gestational diabetes)

Answer 10

Time: Target:

Fasting 5.3 mmol/l

1 hour after meals 7.8 mmol/l, or:

2 hour after meals 6.4 mmol/l