QuestionSBA
QuestionChoice
This is a sensible and potentially useful option, but it is not the best next step in management, since the oral glucose tolerance test at 24-28 weeks will detect cases of gestational diabetes more sensitively than routine glucose monitoring at home.
53314
c
Advise patient to self-monitor their own blood glucose levels at home
QuestionChoice
An immediate oral glucose tolerance test at booking is offered in patients with previous gestational diabetes. If this is normal, then it is repeated at 24-28 weeks. This is the patient's first pregnancy and so she has never been diagnosed with gestational diabetes in the past.
53313
b
Offer an oral glucose tolerance test immediately
QuestionChoice
This patient is at risk for developing gestational diabetes as she has a BMI greater than 30kg/m². All patients with a risk factor should be offered an 2 hour 75g OGTT at 24-28 weeks. As per NICE guidelines, other risk factors include a previous macrosomic baby weighing 4.5kg or above, previous gestational diabetes, a first-degree relative with diabetes, or minority ethnic family origin with a high prevalence of diabetes. It is important to diagnose gestational diabetes early in order to get good control, to reduce risk of foetal macrosomia, neonatal hypoglycaemia, and shoulder dystocia. NICE suggests a diagnosis of gestational diabetes can be made if: a fasting blood sugar is 5.6 mmol/litre or above, or a 2-hour plasma glucose level is 7.8 mmol/litre or above
53312
a
Offer an oral glucose tolerance test at 24 weeks
QuestionChoice
Metformin may be used used if gestational diabetes is confirmed, which is not the case at present in this patient.  Lifestyle advice is offered first in patients with gestational diabetes, and if adequate glucose targets are not met within 1-2 weeks, metformin is started. Insulin is the next step or alternative if metformin cannot be used.
53315
d
Start metformin
QuestionChoice
This may be a suitable plan if the patient had confirmed gestational diabetes. However, in this case, the diagnosis has yet to be confirmed.
53316
e
Advise patient regarding diet and exercise, and prescribe insulin
QuestionComment
Worth noting that those with previous gestational diabetes also have an OGTT at booking, since neither the explanation or notes clarify this...
25247
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subscriber
amygdala
QuestionComment
Can you diagnose T2D in pregnant patients? 
29009
QuestionComment
pretty sure its just gestational diabetes at that point 
55314
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editor
deleted_user
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Zygomatic Pelvis
Concept
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# Summary

Gestational Diabetes Mellitus (GDM) is a condition of glucose intolerance that begins or is first detected during pregnancy, leading to insulin resistance. It affects approximately 5% of pregnancies and poses an increased risk of type 2 diabetes development. The condition is more prevalent among women from ethnic backgrounds with a high prevalence of type 2 diabetes, those with a previous history of GDM, and obese women. GDM may lead to complications such as macrosomia, shoulder dystocia, pre-term delivery, neonatal respiratory distress syndrome, and maternal hypertension, including perinatal complications. Management strategies typically involve a low glycemic index diet, regular physical activity, medication (metformin or insulin) based on specific glucose levels, and postpartum glucose testing to ensure resolution.


# Definition 

Gestational Diabetes Mellitus (GDM) is defined as glucose intolerance with fasting blood glucose levels equal to or above 5.6 mmol/L or 2-hour plasma glucose levels equal to or above 7.8 mmol/L on a 75g Oral Glucose Tolerance Test (OGTT).


# Epidemiology

Approximately 5% of pregnancies are affected by GDM. Women diagnosed with GDM have an increased risk of developing type 2 diabetes, with up to a 50% chance within 5-10 years postpartum.


# Risk Factors



- Ethnic backgrounds with a high prevalence of type 2 diabetes (e.g., Middle Eastern, South Asian, and Afro-Caribbean)
- Prior history of GDM
- Prior delivery of macrosomic babies (>4.5kg)
- History of stillbirth or perinatal death
- Maternal obesity (BMI>30)
- Diabetes in first-degree relatives


# Signs and Symptoms



GDM often presents with no noticeable symptoms. However, some women may experience:

- Polyuria
- Thirst
- Fatigue


# Differential Diagnosis


- Type 1 or Type 2 Diabetes Mellitus: Generally presents with symptoms outside of pregnancy, including potential weight loss
- Other forms of gestational hyperglycaemia: These can be identified through early pregnancy HbA1c testing

# Investigations


Diagnosis of GDM is based on a 75g OGTT:

- Fasting blood glucose level (fasting glucose ≥5.6 mmol/L)
- 2-hour plasma glucose level (2-hour glucose ≥7.8 mmol/L)

This can be remembered as 'diagnosis of GDM is as easy as 5678'

Additional tests may include:

- HbA1c: Helpful in distinguishing between gestational and pre-existing diabetes early in pregnancy
- Urinalysis: To check for glycosuria

# Foetal Complications

- Macrosomia (birthweight >4kg): Excess maternal glucose crossing the placenta and inducing increased fetal insulin production can lead to macrosomia, increasing the risk of shoulder dystocia, birth injuries, and emergency caesarean section
- Increased risk of sacral agenesis in the developing foetus
- Pre-term delivery: May cause neonatal respiratory distress syndrome
- Neonatal hypoglycaemia: High fetal insulin levels after delivery may lead to hypoglycaemia, which if severe, may result in seizures in the baby
- Long-term risk: Increased risk of the baby developing type 2 diabetes later in life

# Maternal Complications

- Increased risk of hypertension and pre-eclampsia
- Future risk: Increased risk of developing type 2 diabetes and GDM in subsequent pregnancies

# Management

Management of GDM depends on specific glucose levels:

- Lifestyle modifications, such as adopting a low glycemic index diet and regular physical activity, are the initial approach when fasting glucose levels are <7 mmol/L.
	- If blood glucose targets are not met with diet and exercise changes within 1 to 2 weeks, offer metformin.
- If fasting glucose levels are ≥7 mmol/L, insulin therapy with or without metformin is often the first-line treatment.
- Advise pregnant women with any form of diabetes to maintain their capillary plasma glucose below the following targets, if these are achievable without causing problematic hypoglycaemia:
	- Fasting: 5.3 mmol/litre
	- 1 hour after meals: 7.8 mmol/litre
	- 2 hours after meals: 6.4 mmol/litre
- Postpartum management includes glucose testing to ensure resolution of GDM and long-term follow-up due to the increased risk of future type 2 diabetes.


# NICE Guidelines

[NICE CKS on Gestational Diabetes](https://www.nice.org.uk/guidance/ng3)


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Gestational Diabetes
Topic
38
Obstetrics
Condition
216
Diabetes in pregnancy (gestational and pre-existing)
UkmlaTopic
18
Obstetrics and gynaecology
10723
Pregnant women with a BMI over 30kg/m² should be screened for gestational diabetes with an oral glucose tolerance test at 24-28 weeks.
Presentation
409
Normal pregnancy and antenatal care
UkmlaTopic
18
Obstetrics and gynaecology
A 27-year-old pregnant female presents to the maternity unit for her booking appointment. This is her first pregnancy and she is currently fit and well. She has no significant past medical history and is currently taking folic acid tablets daily. Her height and weight is recorded by the nurse and her body mass index (BMI) is calculated as 32kg/m². Her fasting blood sugar is 5.2 mmol/litre (3.5-5.5 mmol/L).


Which of the following is the next best step in the management of this patient?
a