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Foundation Sciences · Genetics

Antenatal Genetic Screening (NIPT)

⏱️ 30 mins read 📖 Genetics 🎯 MLA Relevance: High

Antenatal screening in the UK combines maternal serum biochemistry, ultrasound and non-invasive prenatal testing (NIPT) using cell-free foetal DNA.

📌 Learning Objectives

  • Describe the underlying mechanism of Antenatal Genetic Screening (NIPT).
  • Identify the key clinical features and complications of Antenatal Genetic Screening (NIPT).
  • Outline the appropriate investigations and management of Antenatal Genetic Screening (NIPT).
  • Discuss the implications for patients and families of Antenatal Genetic Screening (NIPT).
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Curriculum Mapped
UK MLA Curriculum

📋 Overview

Combined test (11–14 weeks): NT, PAPP-A, β-hCG. Quadruple test (14–20 weeks). NIPT analyses placental cfDNA in maternal blood for high-risk pregnancies.

🔬 Basic Science

Combined test (11–14 weeks): NT, PAPP-A, β-hCG. Quadruple test (14–20 weeks). NIPT analyses placental cfDNA in maternal blood for high-risk pregnancies.

🏥 Clinical Relevance

NIPT detection rates for T21 exceed 99% with very low false positive rates.

🧪 Investigations

Investigation depends on clinical context: relevant blood tests, imaging, and specific genetic or histopathological tests as appropriate. Refer to specialist services where indicated.

💊 Management

Management is condition-specific and typically multidisciplinary, combining medical therapy, surgical intervention where appropriate, supportive care, and family/genetic counselling.

Revision Resources – expand the sections below for high-yield notes, exam pearls, key facts and further reading.

🎯 MLA High-Yield Notes & Quick Revision ⌄
Common SBA themes: recognising the underlying mechanism, identifying classic clinical features, and choosing the first-line investigation or management step. Watch for inheritance pattern and characteristic associations.
nipt cffdna combined test cvs amniocentesis
  • Combined test (11–14 weeks): nuchal translucency, PAPP-A, β-hCG.
  • NIPT analyses placental cell-free DNA in maternal blood.
  • NIPT detection of T21 is >99% with low false-positive rate.
  • Definitive diagnosis requires invasive testing: CVS (11–14 weeks) or amniocentesis (>15 weeks).
  • NHS NIPT is offered as a contingent test for higher-risk pregnancies.
⭐ Exam Pearls ⌄
⭐ High Yield
Combined test (11–14 weeks): nuchal translucency, PAPP-A, β-hCG.
NIPT analyses placental cell-free DNA in maternal blood.
NIPT detection of T21 is >99% with low false-positive rate.
Definitive diagnosis requires invasive testing: CVS (11–14 weeks) or amniocentesis (>15 weeks).
NHS NIPT is offered as a contingent test for higher-risk pregnancies.
💡 Clinical Pearl
Nipt: NIPT detection rates for T21 exceed 99% with very low false positive rates.
⚠️ Exam Tip — Common Mistakes
Confusing the mechanism of Antenatal Genetic Screening (NIPT) with related conditions.
Missing classic clinical features of Antenatal Genetic Screening (NIPT) in SBA stems.
Failing to consider Antenatal Genetic Screening (NIPT) in the differential diagnosis.
🔑 Key Facts ⌄
Combined test (11–14 weeks): nuchal translucency, PAPP-A, β-hCG.
NIPT analyses placental cell-free DNA in maternal blood.
NIPT detection of T21 is >99% with low false-positive rate.
Definitive diagnosis requires invasive testing: CVS (11–14 weeks) or amniocentesis (>15 weeks).
NHS NIPT is offered as a contingent test for higher-risk pregnancies.
🔗 Related Topics ⌄
📚 Antenatal Screening 📚 Down Syndrome 🔬 Genetic Counselling Foundation Sciences →
📚 References ⌄
  1. GMC MLA Content Map
  2. NICE Clinical Knowledge Summaries
  3. BMJ Best Practice

Further Resources

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