What is the UK definition of a live birth?

A child born alive, defined by WHO as the complete expulsion or extraction from the mother of a product of conception that shows any evidence of life.

Which term is used synonymously with stillbirth according to WHO?

Fetal death.

How is maternal mortality ratio expressed?

As the ratio of deaths to 100,000 live births.

What is the minimum weight or gestational age for a stillbirth to be included in national statistics according to WHO?

Weight at least 500 g or gestational age at least 22 weeks.

In obstetric epidemiology, what is the significance of clear definitions?

Clear definitions are essential for effective counting and resource allocation.

What constitutes maternal death according to WHO?

Death of a woman while pregnant or within 42 days of pregnancy termination from any cause related to or aggravated by pregnancy.

Which statistical measure indicates the proportion of true positives in a diagnostic test?

Sensitivity or true positive rate (TPR).

What is the typical maternal mortality ratio in developed countries like the UK?

Around 10 per 100,000 live births.

What defines a stillbirth in the UK?

A child born after the 24th week of pregnancy that did not breathe or show any life signs after expulsion.

What is the role of Bayes' theorem in clinical diagnosis?

It allows clinicians to calculate posterior odds from prior odds and likelihood ratios based on test results.

What is the predictive value positive in a diagnostic test?

The probability that a patient actually has the disease given a positive test result.

How does the cut-off value in a diagnostic test affect its performance?

Varying the cut-off changes sensitivity and specificity, impacting the rate of true and false positives.

What is the significance of the Receiver Operator Characteristic (ROC) curve?

It illustrates the trade-off between sensitivity and specificity at different cut-off values.

What is a common bias found in treatment comparisons within clinical studies?

Systematic differences between treatment and control groups, which can mislead results.

What is the definition of type 1 error in statistical testing?

Failing to realize a real difference exists, leading to a false positive result.

Which factor can lead to a type 2 error?

Failing to detect a real effect due to insufficient sample size.

What is the effect of varying disease prevalence on predictive values?

Predictive values vary with disease prevalence, affecting the interpretation of test results.

What is the primary purpose of conducting a meta-analysis?

To combine results from multiple studies to provide a more comprehensive understanding of treatment effects.

What defines a direct maternal death?

Death resulting from complications of pregnancy or treatment directly related to pregnancy.

What is the formula for calculating odds ratios (OR)?

OR = (a/c) / (b/d), where a and b are outcomes in treatment and control groups.

What is the importance of blinding in clinical trials?

To prevent bias in outcome assessment by ensuring neither the investigator nor the patient knows the treatment allocation.

What does specificity (TNR) measure in diagnostic testing?

The proportion of true negatives correctly identified by the test.

What distinguishes direct from indirect maternal deaths?

Direct deaths arise from pregnancy complications, while indirect deaths are due to pre-existing or unrelated diseases exacerbated by pregnancy.

How can biases in clinical trials be minimized?

By using randomization to allocate participants to treatment or control groups.

What is the consequence of high compliance in clinical trials?

It enhances the ability to determine the efficacy of a treatment.

What are predictive values and how do they relate to clinical testing?

Predictive values indicate the likelihood of a patient having a disease based on test results, crucial for clinical decision-making.

What is the conventional threshold for statistical significance in clinical studies?

A p-value of less than 0.05.

What does the term 'fetal death' refer to in obstetric terminology?

Death before the complete expulsion or extraction from the mother of a product of conception.

What is the primary distinction between live birth and stillbirth?

Live birth involves evidence of life after birth, while stillbirth is defined as no signs of life after expulsion.

What is the significance of the 42-day period in maternal mortality statistics?

It marks the timeframe in which maternal deaths are counted as related to pregnancy.