Gestational Diabetes Screening Review

Questions and Answers

What method involves the measurement of plasma?

HAPO

What plasma glucose cut-off was proposed by colleagues to achieve 100% sensitivity?

4.6 mmol / l

4.0 mmol / l

4.4 mmol / l (correct)

4.2 mmol / l

Dropping the fasting plasma glucose cut-off to 4.4 mmol / l increased specificity by 27%.

False

What is the main limitation of fasting plasma glucose in gestational diabetes?

Poor sensitivity Signup and view all the answers

What does OGTT stand for?

Oral Glucose Tolerance Test Signup and view all the answers

What is a potential consequence of gestational diabetes for the mother?

Up to 50% risk of future diabetes Signup and view all the answers

Evidence has shown a clear benefit of early detection in gestational diabetes.

False Signup and view all the answers

Which method currently has better sensitivity and specificity for detecting gestational diabetes?

Oral Glucose Tolerance Test (OGTT) Signup and view all the answers

Gestational diabetes is carbohydrate intolerance diagnosed during _____ .

pregnancy Signup and view all the answers

Match the type of diabetes to the statement:

Type 2 diabetes = Major cause of blindness and renal disease Gestational diabetes = Up to 50% risk of future diabetes for the mother Signup and view all the answers

What is gestational diabetes?

Carbohydrate intolerance with onset or first recognition of hyperglycaemia during pregnancy. Signup and view all the answers

What are the risks associated with gestational diabetes? (Select all that apply)

Postpartum Type 2 diabetes Signup and view all the answers

What are some factors that increase the risk of developing gestational diabetes?

Obesity, first-degree relative with diabetes, high-risk ethnic groups (Hispanic, Black, Native American, etc.), previous gestational diabetes. Signup and view all the answers

Gestational diabetes is best recognized in the ______ state during late gestation.

fed Signup and view all the answers

What test is commonly used to diagnose gestational diabetes?

Oral glucose tolerance test Signup and view all the answers

Gestational diabetes can be associated with increased rates of malformations.

False Signup and view all the answers

Which glucose tolerance tests are mentioned in relation to gestational diabetes screening? (Select all that apply)

3 h / 100-g test Signup and view all the answers

What percentage of women who have had gestational diabetes may develop Type 2 diabetes postpartum?

Up to 50% after 10 years. Signup and view all the answers

Match the following risks or definitions to the respective terms related to gestational diabetes:

Fetal macrosomia = Large for gestational age infant due to increased maternal glucose Polycystic ovarian syndrome = A condition that is a potential risk factor for gestational diabetes Gestational hypertension = Increased blood pressure that can occur during pregnancy Macrosomic fetus = A fetus that is significantly larger than average Signup and view all the answers

Screening for gestational diabetes is universally agreed upon as necessary.

False Signup and view all the answers

What percentage of participating clinicians followed the well-established cut-off values for the 50-g test?

40% Signup and view all the answers

What was the rate of large-for-gestational age with mild gestational hyperglycaemia?

22.1% Signup and view all the answers

The American College of Obstetricians and Gynaecologists recommends universal screening between 24 and 28 weeks gestation.

True Signup and view all the answers

Which of the following methods is convenient and cost-effective for monitoring gestational diabetes?

Glycosylated haemoglobin (HbA1c) Signup and view all the answers

What is an indication of hyperglycaemia outside of pregnancy?

Diabetes Signup and view all the answers

The predictive value of the glucose challenge test varies significantly with __________.

ethnicity Signup and view all the answers

What was the prevalence of gestational diabetes in teenage pregnancies in Hong Kong?

5.4% Signup and view all the answers

Lowering cut-off values for glucose screening can enhance sensitivity without affecting specificity.

False Signup and view all the answers

What was the sensitivity of the 50-g screen according to a recent study?

59% Signup and view all the answers

What was the cut-off value used for fasting plasma glucose that appeared encouraging?

4.1 mmol/l Signup and view all the answers

What screening method was found to have the highest specificity when evaluated?

Fasting plasma glucose Signup and view all the answers

The WHO 2-h 75-g test has a greater predictive value than the more cumbersome __________ test.

NDDG 3-h 100-g Signup and view all the answers

Which organization recommends universal screening for gestational diabetes between 24 and 28 weeks of gestation?

The American College of Obstetricians and Gynaecologists Signup and view all the answers

The American Diabetes Association recommends universal screening for gestational diabetes.

False Signup and view all the answers

What is a limitation of the oral glucose tolerance test?

It's unrelated to body weight Signup and view all the answers

The sensitivity of the 50-g screen improves significantly with varying ________ values.

ethnic Signup and view all the answers

What is the impact of relaxing the 2-h value of the 75-g test on specificity?

It was evaluated by comparing the outcome of those with values of 8-9 mmol/l with those with < 8 mmol/l. Signup and view all the answers

What was the sensitivity of the 50-g screen in a recent study?

59% Signup and view all the answers

Match the following screening methods with their sensitivity:

Random plasma glucose = 40% HbA1c = 40% Fasting plasma glucose (4.8 mmol/l) = 81% Fasting plasma glucose (4.9 mmol/l) = 88% Fasting plasma glucose (4.1 mmol/l) = 92% Glucose tolerance test (NDDG) = 79% Signup and view all the answers

Glycosuria is a cheap and convenient screening method that has ________ specificity.

low Signup and view all the answers

What is the sensitivity and specificity of random plasma glucose as identified in the study?

40% sensitivity and 90% specificity. Signup and view all the answers

What is the predicted fasting plasma glucose cut-off value that could rule out gestational diabetes with over 90% sensitivity?

4.4 mmol/l Signup and view all the answers

What does the DECODE study aim to identify?

Whether screening for gestational diabetes is worthwhile Signup and view all the answers

Half of the cases with impaired fasting glucose would be detected by glucose tolerance testing.

True Signup and view all the answers

What screening method remains the most accepted diagnostic test for gestational diabetes?

Oral Glucose Tolerance Test (OGTT) Signup and view all the answers

What is a limitation of random plasma glucose as a screening method for gestational diabetes?

It has poor sensitivity. Signup and view all the answers

There is an up to ______% risk of future diabetes in the mother associated with gestational diabetes.

50 Signup and view all the answers

Match the following aspects between Type 2 diabetes and gestational diabetes:

Evidence of public health importance = Major cause of blindness Safe and effective screening methods = No universally agreed guidelines Improved prognosis with early detection = Some evidence for improved perinatal morbidity Evidence supporting cost-effectiveness = Needs to be investigated Signup and view all the answers

What is gestational diabetes defined as?

Carbohydrate intolerance resulting in hyperglycaemia Signup and view all the answers

Gestational diabetes is associated with an increased rate of malformations.

False Signup and view all the answers

What percentage of women with gestational diabetes may develop postpartum Type 2 diabetes after 10 years?

50% Signup and view all the answers

The ___ tolerance test is considered the most acceptable diagnostic test for gestational diabetes.

oral glucose Signup and view all the answers

What are the recommended glucose challenge tests for gestational diabetes screening?

All of the above Signup and view all the answers

What is the main reason for using a glucose challenge test in pregnancy?

Physiological changes in normal pregnancy. Signup and view all the answers

Elevated fasting or random plasma glucose levels greater than ___ mmol/l are a risk factor for gestational diabetes.

7 Signup and view all the answers

Which of the following groups is considered at high risk for gestational diabetes?

All of the above Signup and view all the answers

What is the potential disadvantage of screening for gestational diabetes?

All of the above Signup and view all the answers

What is the recent recommendation for the fasting plasma glucose cut-off value in screening for gestational diabetes according to the modified Carpenter and Coustan criteria?

6 mmol/l Signup and view all the answers

The debate on whether to screen for gestational diabetes will be resolved without further research.

False Signup and view all the answers

Study Notes

Gestational Diabetes Overview

Defined as carbohydrate intolerance leading to hyperglycaemia recognized first during pregnancy.
Association with adverse maternal and fetal outcomes underscores the need for screening.

Historical Context of Screening

Earlier tests including glycosuria and HbA1c lacked sensitivity, paving the way for glucose tolerance tests.
The glucose challenge is based on physiological pregnancy changes affecting insulin sensitivity and post-prandial glucose levels.

Current Screening Practices

Vary by region; e.g., USA recommends a 50-g oral glucose load initially, followed by a 3-h 100-g test if needed.
WHO advocates for a 75-g, 2-h glucose tolerance test, performed ideally between 24-28 weeks of gestation.
European and UK practices show discrepancies, with some centers using 75-g tests, while others employ a two-step approach.

Cut-off Values for Diagnosis

Different organizations have varying criteria for diagnosing gestational diabetes based on glucose tolerance tests.
The ADA guidelines set specific cut-off points while the WHO criteria are recognized for their simplicity and inclusivity.

Screening Debate

Ongoing debate on the efficacy and necessity of universal vs. selective screening for gestational diabetes.
Critics highlight potential overdiagnosis leading to unnecessary interventions, such as higher rates of caesarean sections.

Risk Factors for Gestational Diabetes

Key risk factors include obesity, family history of diabetes, specific ethnic backgrounds, elevated glucose levels, and past gestational diabetes.

Long-term Effects

About 50% of women with a history of gestational diabetes may develop Type 2 diabetes within 10 years, especially if insulin was used during pregnancy.

Limitations of Current Testing Methods

Oral glucose tolerance tests are time-consuming, costly, and may be uncomfortable.
The practical limitations and reproducibility issues of different glucose tests are critical considerations for broader adoption.

Importance of Research

Continued research is necessary to resolve questions around screening protocols, particularly regarding the impact of intervention on maternal and neonatal outcomes.
Studies emphasize the correlation between gestational diabetes and adverse pregnancy outcomes, thereby reinforcing the case for vigilant screening practices.### Limitations of Oral Glucose Tolerance Test (OGTT)
High cost and time-consuming process.
Unpleasant experience, particularly for pregnant women.
Not reflective of physiological conditions.
Ineffective correlation with body weight.
Established cut-off values frequently disregarded, leading to significant misinterpretation in up to 60% of cases.
Generally limited to individuals over 25 years; however, emerging research highlights increased risk in teenagers.
Predictive accuracy varies by ethnic background.
Reproducibility issues in up to 24% of tests.
Lowering cut-off values enhances sensitivity but reduces specificity.

Ethnic Impact on Glucose Tolerance Tests

Significant variance in test results based on ethnicity, as observed with different sensitivity rates among ethnic groups.
Positive responses to the 50-g screen illustrate ethnic disparities: Whites (27%), Blacks (18%), Asians (41%), Filipinos (31%).
Adjusting the cut-off of the 50-g screen increases sensitivity but lowers specificity significantly.

Reproducibility of Results

90% normal responses are reproducible on retest, while only 83% of abnormal results hold consistency.
Poor sensitivity of 59% noted in recent studies linked to the timing post-meal before the test.

Alternative Screening Methods

Glycosuria: Simple and inexpensive, but lacks specificity due to reduced renal threshold during pregnancy. A study showed only 1% of women with glycosuria had abnormal glucose tolerance.
Glycosylated Hemoglobin (HbA1c): Convenient but not sensitive enough for gestational diabetes screening; poorly correlates with timely glucose changes.
Random Plasma Glucose: Popular since the 1980s; however, lacks sensitivity, especially in the third trimester.

Fasting Plasma Glucose (FPG) as a Screening Method

Rising prominence due to recent ADA and WHO guidelines emphasizing its use.
Studies show varying cut-off values yield different sensitivities and specificities.
A multiethnic study demonstrated a 90% accuracy in ruling out or validating gestational diabetes based on specific cut-off values.

Summary of Fasting Plasma Glucose Studies

Comparison of two studies highlights mixed results but suggests FPG is a viable option for screening.
Specificity and sensitivity drop when using lower cut-off values, necessitating further testing for many pregnant women.

Overall Assessment of Screening Methods

Only fasting plasma glucose shows sensitivity and specificity closely matching OGTT.
Concerns about the adequacy of other methods highlight the need for ongoing research into effective screening practices for gestational diabetes.
Future studies, like the HAPO study, aim to clarify the relationship between plasma glucose levels and pregnancy outcomes.

Screening for Gestational Diabetes – Future Directions

Fasting plasma glucose, while promising, has limitations and may miss cases in early post-prandial phases.
Incorporation of different ethnic cut-off values may enhance detection but poses practical challenges.
The need for robust, validated guidelines remains critical for the future of gestational diabetes screening.### Gestational Diabetes Overview
Gestational diabetes is carbohydrate intolerance with hyperglycaemia identified during pregnancy.
It can result in adverse maternal and fetal outcomes, warranting the need for screening.
The association between gestational hyperglycaemia and complications in pregnancy has been emphasized in various studies.

Screening Issues

Screening for gestational diabetes is debated due to concerns over clinical judgment bias, potentially leading to unnecessary interventions like cesarean sections.
A lack of definitive data regarding glycaemic thresholds and the efficacy of interventions limits the justification for widespread screening.

Testing Methods

Common tests include the 1-hour/50-g, 2-hour/75-g, and 3-hour/100-g oral glucose tolerance tests (OGTT).
Challenges include time and costs, along with adverse physiological effects of glucose loads unrelated to body weight.
Random glucose tests have inadequate sensitivity for routine screening; however, fasting glucose shows promise but requires additional validation.

Diagnostic Standards

OGTT is the established standard diagnostic test for gestational diabetes despite its limitations.
More convenient screening methods like fasting or post-load glucose need validation against OGTT to gain acceptance.

Long-term Implications

Women diagnosed with gestational diabetes have approximately a 50% risk of developing Type 2 diabetes within 10 years.
The risk increases for those who required insulin during pregnancy or had macrosomic infants.

Recurrence and Risks

Recurrence of gestational diabetes in subsequent pregnancies is reported in 20-50% of cases.
Increased maternal glucose levels may lead to fetal complications such as macrosomia, hypo-calcaemia, and other disorders.

Risk Factors

Key risk factors for gestational diabetes include obesity (BMI ≥ 27), a family history of diabetes, and other health issues related to insulin sensitivity.

Need for Comprehensive Studies

Further studies are necessary to determine the influence of interventions on maternal and fetal outcomes in high-risk pregnancies.
Reliable and practical screening protocols are essential for improving gestational diabetes detection and management.

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Description

This quiz reviews the past, present, and future of screening for gestational diabetes. Explore the developments in diagnosis and management of carbohydrate intolerance during pregnancy. Test your knowledge on this important topic in women's health.