Prenatal screening ppt
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Questions and Answers

What is the primary benefit of prenatal screening for chromosomal abnormalities?

  • Guaranteed detection of all abnormalities
  • Parental reassurance if normal (correct)
  • Increased risk of miscarriage
  • Immediate delivery if an abnormality is detected

    • What percentage of pregnancies have recognizable chromosomal abnormalities?

  • 1 in 200
  • 1 in 100
  • 1 in 400
  • 1 in 300 (correct)

    • Which screening method is noted as the most sensitive and specific for detecting fetal aneuploidies?

  • Chorionic villus sampling
  • Cell-Free DNA testing (correct)
  • First trimester screening
  • Quad screening

    • What is a common risk associated with abnormal prenatal screening results?

    <p>Increased anxiety among parents</p> Signup and view all the answers

    Which statistical finding is most common among recognized chromosomal abnormalities?

    <p>Trisomy 21</p> Signup and view all the answers

    What percentage of recognized chromosomal abnormalities are accounted for by Trisomy 21, 18, and 13?

    <p>95%</p> Signup and view all the answers

    What should be offered if an abnormal screening test is identified?

    <p>Genetic counseling and further testing</p> Signup and view all the answers

    What is a significant risk of prenatal screening and diagnosis?

    <p>False positive results</p> Signup and view all the answers

    What chromosomal condition is associated with the absence of the fetal nasal bone during the first trimester?

    <p>Down syndrome (trisomy 21)</p> Signup and view all the answers

    What is the risk of neural tube defects in pregnancies involving patients with a personal history of a pregnancy with an NTD?

    <p>1/30 pregnancies</p> Signup and view all the answers

    Which of the following substances is a component of quad screening for neural tube defects?

    <p>Pregnancy-associated plasma protein A</p> Signup and view all the answers

    At what gestational age can chorionic villus sampling (CVS) be performed?

    <p>10-13 weeks</p> Signup and view all the answers

    What is the main purpose of the first trimester serum screening?

    <p>To evaluate chromosomal abnormalities</p> Signup and view all the answers

    Which group should receive daily folic acid requirements of 4 mg during pregnancy?

    <p>At-risk pregnancies</p> Signup and view all the answers

    What does a positive screening test for fetal aneuploidy indicate?

    <p>A need for genetic counseling and comprehensive ultrasound evaluation</p> Signup and view all the answers

    Which procedure is diagnostic for genetic conditions and involves a miscarriage risk?

    <p>Amniocentesis</p> Signup and view all the answers

    When is the second trimester ultrasound typically performed for assessing fetal structural defects?

    <p>18-22 weeks</p> Signup and view all the answers

    Which factor does NOT increase the risk of neural tube defects?

    <p>Adequate folic acid intake</p> Signup and view all the answers

    What is a key consideration for patients when offered prenatal genetic screening and diagnostic testing?

    <p>Patients have the right to pursue or decline any prenatal testing.</p> Signup and view all the answers

    Which of the following factors is associated with an increased risk of chromosomal abnormalities in pregnancies?

    <p>Increasing maternal age</p> Signup and view all the answers

    What is a potential consequence of receiving an abnormal prenatal screening result?

    <p>Increased parental anxiety and further testing options</p> Signup and view all the answers

    The quad screening conducted during the second trimester assesses for which of the following?

    <p>Down syndrome, Trisomy 18, and neural tube defects</p> Signup and view all the answers

    What is an important limitation associated with the cell-free DNA screening method?

    <p>False negatives can occur, potentially leading to missed conditions.</p> Signup and view all the answers

    Study Notes

    Prenatal Screening for Chromosomal Abnormalities

    • Approximately 1 in 300 pregnancies have detectable chromosomal abnormalities.
    • Most common abnormalities are Trisomy 21 (Down syndrome), Trisomy 18, Trisomy 13, and X/Y chromosome changes.
    • Maternal age is a significant risk factor for chromosomal abnormalities.
    • Many pregnancies with chromosomal abnormalities do not reach the second trimester.

    Prenatal Screening/Testing Recommendations

    • All pregnant individuals should be offered prenatal genetic screening and diagnostic testing, regardless of age or risk factors.
    • Decisions about screening and diagnostic testing are the patient's choice.
    • Individuals with positive screening results should receive genetic counseling and invasive diagnostic testing for genetic conditions, as well as a comprehensive ultrasound (18-22 weeks).

    Risk Assessment (Down Syndrome)

    • Down syndrome is a more prevalent chromosomal abnormality among fetuses in the third trimester.

    Benefits of Prenatal Screening/Diagnosis

    • Provides reassurance (if results are normal).
    • Allows for knowledge of chromosomal/other abnormalities.
    • Offers increased options for management, including further testing, referrals, and counseling for planned birth or termination.
    • Prepares for a child with special needs.
    • Aids in obstetric/neonatal management.

    Risks of Prenatal Screening/Diagnosis

    • Potential for parental anxiety (from abnormal results).
    • Possibility of false positive results.
    • Risk of pregnancy complications such as premature rupture of membranes (PROM), infection, preterm labor (PTL).
    • Risk of pregnancy loss.

    Prenatal Screening Options

    • Cell-free DNA (cfDNA): Maternal blood test detecting fetal DNA for common aneuploidies, including Down syndrome, Edwards syndrome, Patau syndrome, and sex chromosome abnormalities. Sensitive and specific, but not definitive, false negatives are possible, and can be performed as early as 10 weeks.
    • First Trimester Screening: Nuchal translucency (NT) ultrasound and maternal serum markers (β-hCG and PAPP-A) to calculate chromosomal abnormality risk.
      • Nuchal translucency: Widening of posterior neck area in the embryo is a sign of potential abnormality
      • Nasal bone: Absence of a nasal bone can indicate chromosomal abnormalities.
    • Second Trimester Screening: Quadruple screening (AFP, inhibin-A, hCG, estriol) and anatomical ultrasound to evaluate for structural defects.

    Neural Tube Defects (NTDs)

    • Approximately 1 in 1,000 pregnancies involve NTDs. NTD risk is higher in patients with prior NTD pregnancies.
    • Risk factors include low folic acid intake, seizure medications, diabetes, and genetic predisposition.
    • Folic Acid Recommendations: 400 mcg daily for typical pregnancies; 4,000 mcg daily for pregnancies at high risk (prior NTD, seizure disorders, diabetes, family history).
    • Screening: Quadruple screening and second-trimester ultrasound (18-22 weeks).
    • Diagnostic: Chorionic villus sampling (CVS) or amniocentesis.

    Diagnostic Tests

    • Chorionic villus sampling (CVS): First trimester procedure (10-13 weeks) with a miscarriage risk of 1/100-1/200
    • Amniocentesis: Second trimester procedure (15-22 weeks) with a miscarriage risk of 1/200-1/500

    Trimester Breakdown

    • First trimester: Weeks 1-13
    • Second trimester: Weeks 14-27
    • Third trimester: Weeks 28-40

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    Description

    This quiz focuses on prenatal screening for chromosomal abnormalities, including risks, recommendations, and specific conditions like Down syndrome. It highlights the importance of genetic testing and counseling for expecting parents. Test your understanding of maternal age factors and screening options available.

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