Diabetic Ketoacidosis in Pregnancy

Diabetic ketoacidosis in pregnancy is a life-threatening state of insulin deficiency with hyperglycaemia, ketosis and metabolic acidosis. It occurs in type 1 diabetes, and sometimes in type 2 or gestational diabetes, and develops at lower glucose than in the non pregnant state. It is triggered by infection, vomiting, missed insulin, antenatal steroids and beta agonist drugs. Fetal loss is common and maternal death is possible.

• May occur at glucose below 11 mmol/L (euglycaemic).
• Pregnancy lowers bicarbonate, so acidosis worsens faster.
• Treat the mother first; the fetus improves with her.

Women have nausea, vomiting, abdominal pain, thirst, polyuria, drowsiness and deep rapid breathing with fruity breath, dehydration and tachycardia. Fetal heart may show abnormal tracing.

• Respiratory rate above 24 per minute.
• Abdominal pain may mimic labour or abruption.
• Differential diagnosis: hyperemesis with ketosis, starvation ketosis, sepsis, appendicitis, pancreatitis, abruption, labour.
• Complications: cerebral oedema, hypokalaemia, hypoglycaemia during treatment, acute kidney injury, venous thrombosis, fetal death, preterm labour, maternal death.

The approach is blood tests, urine ketones and a search for the cause.

• Capillary or laboratory glucose (often above 11 mmol/L), urine ketones 2 plus or more, blood ketones above 3 mmol/L.
• Venous blood gas: pH below 7.30 or bicarbonate below 15 mmol/L.
• Urea, creatinine, sodium, potassium (note the starting level), full blood count, blood culture, urine culture, malaria test.
• ECG, chest X-ray, cardiotocography after stabilisation.

The principle is IV fluids, fixed rate insulin and potassium replacement with intensive monitoring.

• Supportive: admit to high dependency; oxygen to keep saturation above 95 percent; left lateral position; urinary catheter; hourly glucose and ketones; potassium 2-hourly; search and treat infection.
• Pharmacological: sodium chloride 0.9 percent 1 litre over the first hour, then 1 litre over 2 hours, then 1 litre over 4 hours, then 1 litre over 6 hours; soluble insulin 0.1 units/kg/hour IV by infusion (50 units in 50 mL sodium chloride 0.9 percent) after the first fluid litre; add dextrose 10 percent 125 mL/hour when glucose falls below 14 mmol/L, keep insulin running until ketones are below 0.6 mmol/L; potassium chloride 40 mmol per litre if potassium is 3.5 to 5.3 mmol/L, none if above 5.5, and if below 3.5 mmol/L give potassium chloride 10 mmol/hour peripherally with cardiac monitoring before insulin; sodium bicarbonate only if pH is below 6.9 (100 mmol in 400 mL water over 2 hours); enoxaparin 40 mg subcutaneous daily; ceftriaxone 2 g IV daily if infection suspected; then restart subcutaneous insulin when eating and ketones are cleared.
• Procedures: none; emergency delivery only for fetal compromise after maternal stabilisation.
• Special groups: women with renal or cardiac disease receive fluids in 250 mL boluses with reassessment; women on antenatal steroids need insulin increased by 25 to 40 percent for 72 hours.
• Red flags: pH below 7.0, potassium below 3.0 or above 6.0 mmol/L, glucose above 33 mmol/L, confusion, systolic blood pressure below 90 mmHg.
• Follow-up: hourly monitoring in hospital; electrolytes 2-hourly until stable; diabetes educator review before discharge; fetal growth scan at 2 weeks; review insulin dose weekly.