Hypoglycaemia in Pregnancy

Hypoglycaemia in pregnancy is plasma glucose below 3.5 mmol/L, causing sweating, tremor, confusion or loss of consciousness. The commonest cause is insulin or a sulfonylurea in diabetes, especially in the first trimester when insulin needs fall; other causes are vomiting, fasting, alcohol, malaria with quinine, sepsis and adrenal insufficiency. It matters because severe episodes cause seizures, injury and fetal distress.

• Insulin requirements fall at 8 to 14 weeks and after delivery.
• Quinine and severe malaria cause hypoglycaemia in pregnancy.
• Hypoglycaemia unawareness raises the risk.

Women have hunger, sweating, tremor, palpitations, anxiety and headache, progressing to confusion, convulsions and coma. Fetal heart may be abnormal during severe episodes.

• Pulse and blood pressure usually raised early.
• Recovery after glucose.
• Differential diagnosis: eclampsia, epilepsy, stroke, sepsis, severe malaria, alcohol intoxication, adrenal crisis, hyperemesis.
• Complications: seizures, coma, injury, accidents, fetal distress, recurrent severe episodes, brain injury.

The approach is immediate capillary glucose with a search for the cause.

• Capillary glucose below 3.5 mmol/L; severe if the woman needs help or is unconscious.
• Repeat laboratory glucose, urea and electrolytes, full blood count, malaria test.
• Review insulin dose, injection site, timing, meals, exercise and drugs including quinine and sulfonylureas.
• Liver tests, cortisol and ultrasound if no cause is found.

The principle is immediate glucose replacement and correction of the cause.

• Supportive: if awake, give 15 to 20 g fast acting carbohydrate (150 to 200 mL fruit juice or 3 to 4 glucose tablets), recheck in 15 minutes and repeat if below 4 mmol/L; then give a snack; keep the woman left lateral; check fetal heart.
• Pharmacological: if unconscious or unable to swallow give dextrose 10 percent 150 to 200 mL IV over 15 minutes and repeat after 10 minutes if glucose is below 4 mmol/L; or glucagon 1 mg IM or subcutaneous; then give dextrose 10 percent 100 mL/hour until eating; thiamine 100 mg IV before dextrose if alcohol use or hyperemesis; reduce insulin by 10 to 20 percent; for severe malaria give artesunate 2.4 mg/kg IV at 0, 12 and 24 hours then daily, and check glucose 4-hourly.
• Procedures: none.
• Special groups: women on sulfonylureas need admission for 24 to 48 hours with glucose every hour because of prolonged effect; women with adrenal insufficiency give hydrocortisone 100 mg IV; women with hypoglycaemia unawareness keep glucagon at home.
• Red flags: unconsciousness, seizure, glucose below 2.5 mmol/L, failure to respond to glucose.
• Follow-up: review insulin plan within 1 week; teach hypoglycaemia recognition; check glucose 4-hourly for 24 hours after severe episode; fetal movement counts.