Professional and Linguistic Assessments Board (PLAB) Practice Exam

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Prepare for the PLAB Exam with a comprehensive quiz. Test your knowledge with multiple choice questions. Each query includes detailed hints and explanations to ensure you're ready for success on your exam day!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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What is the approximate chance of a 40-year-old having a baby with Down syndrome?

1 in 200
1 in 100
1 in 50
1 in 20

The correct answer is: 1 in 100

The chance of a 40-year-old woman having a baby with Down syndrome is approximately 1 in 100. As a woman ages, particularly after 35, the risk of chromosomal abnormalities, including Down syndrome, increases significantly. This is primarily due to the aging of ovarian eggs which may lead to nondisjunction during meiosis, resulting in an embryo with an extra copy of chromosome 21. Statistical data indicate that for a woman at 40 years of age, the risk increases to around 1 in 100, which reflects this increased likelihood. This risk is based on population studies and genetic assessments of mothers in this age group. The figures represent a general estimate and can vary considerably among individuals, but they provide a useful guideline for understanding the implications of maternal age on genetic risks. The other options would imply a different understanding of the statistical risk associated with maternal age at 40. The chance of 1 in 200 is typically more associated with younger ages, while a risk of 1 in 50 or 1 in 20 would suggest a significantly higher prevalence than what is typically observed at this age.