Gestational Diabetes Mellitus

Question 1

A 28-year-old pregnant woman is found to have a random BSL of 15mmol/L. Discuss diagnosis and management.

Answer 1

Impression
A random BSL of 15mmol/L above diagnostic criteria for diabetes. Am concerned about gestational diabetes (if >20wks gestation), however would also want to rule out pre-existing diabetes and complications of it including DKA/HHS.

Importantly, I am concerned for the fetal implications of this presentation, would want to conduct target Hx/Ex/Ix and manage supportively and definitively.

Question 2

GDM - History

Answer 2

History

• sx: often asymptomatic, but may have frothy urine, polyphagia, polydipsia/polyuria, etc
• other: complications of diabetes: visual change, sensory deficits, etc
• O&G Hx: GTPAL, yellow book, scans and findings, past obstetric Hx (diabetes, weights of previous pregnancies), vaccination, GBS and Rh status
• RISK: fam hx, obesity, previous GDM, PCOS, AMA, previous macrosomia (Ask about weights of past children)
• PMHx, PSHx
• medications/allergies
• psychosocial screen

Question 3

GDM - Examination

Answer 3

Examination

• general appearance + vital signs
• antenatal assessment (FHR doppler, BP, abdo palp, fundal height)
• exclude signs of pre-eclampsia (given increased risk of HTN)

Question 4

GDM - Investigations

Answer 4

Investigations

• Key/Diagnostic: OGTT (Fasting >5.1mmol/L, 1 Hr >10mmol/L), fasting BSL, HbA1C
• bedside: anthropometric, vitals, urinalysis (glycosuria)
• bloods: UEC, rest of antenatal
• Imaging: regular US to assess fetal development

Question 5

GDM - Management

Answer 5

Management
BSL treatment targets:
- fasting: <5mmol/L
- HbA1C: <6%

Components:

• involve MDT of O&G, midwives, diabetes educator, endocrine, dietician
• patient education paramount!

Glycaemic control:
Non-pharm
- lifestyle changes (diet, exercise, smoking cessation etc)
- home BSL monitoring

Pharm

• metformin
• insulin

Delivery

• planned, manage risks associated with macrosomia
• small dose insulin peri-partum
• cease hyperglycaemia meds at onset of labour
• close monitoring of neonates for hypoglycaemia and other complications (congenital heart disease)
• repeat OGTT6wks-12 months postpartum to differentiate GDM from DM.