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25 Cards in this Set
- Front
- Back
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CNM counseling must include:
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Her numerical risk of major disorder screening or dx test may ID
General characteristics of the disorder Tests offered to detect eh disorder: HOW the tests are done RISKS of those test (with %) WHEN the tests are done ACCURACY/LIMITATIONS of tests (with %) NO TESTING equal option |
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Two most important factors is genetic testing for women
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VALUES (her own)
Provider influence |
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Cystic Fibrosis
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Is a genetic disease that makes the body produce thick mucus in lung & GI tract
Both parents must have trait (recessive) All women are to be offered CF screening at the first prenatal visit Done by blood test or saliva testing |
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Down Syndrome
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Baby is born with an extra chromosone 21 and is one of the MOST COMMON chromosome abnormalities
Level of impairment may be mild to severe Approx. 4,000 children with DS are born in US/year or about 1 in every 600-1000 live births Risk increases with maternal age All pregnant women > 35 years of age offered DIAGNOSTIC testing All women < 20 wks gestation are offered DS screening |
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NTD
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Occurs before day 26 post fertilization
Varies in severity from closed spinal defect (occulta) to anecephalcy. Incidence in US approx. .70/1000 Incidence of NTD increased in people of celtic origin: welsh, irish, scotch descent. Highest in Appalachian region About 55-70% of NTD's occur in female Childbearing age women should be taking 0.4 mg of folic acid. All women < 20 wks gestation offered NTD detection via serum screening in 2nd trimester. |
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Quad screen is done when?
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Second trimester
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Integrated screening consists of?
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1st & 2nd trimester serum markers & 1st trimester NT
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Quad screen information:
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Detection rates:
Down syndrome-80% NTD- 75-80% False positive rate- 5% Analytes= BhCG, uncojugated estriol, AFP, & inhibin A Rates analyzed in conjunction with maternal age |
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Quad screen information:
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Best done between 16-18 wks (can be done 15-20 wks)
Results indication NTD= ^AFP, May be dating related-Follow-up=dating USN and possibly amniocentiesis Results indicating DS= ^inhibin A, ^BhCG, decreased estriol and possibly decreased AFP Follow up=Amniocentisis |
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1st trimester screening
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Consists of serum analytes BhCG, PAPP-A PLUS NT.
Detects 85% of DS False positive rate of 5% NT can be done between 10-13 wks Serum markers done 9-13 wks results are analyzed in conjunction with maternal age DOES NOT screen for NTD's |
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Increased NT measurement is associated with an increased risk for:
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Chromosome abnormalities like DS
Major structural cardiac defects & others structural abnormalities SAB, IUFD, SGA, and still birth |
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What is considered increased NT measurement?
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>3.5 mm
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Benefits of 1st trimester screening
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Results available earlier in gestation
Results take about a week Higher detection rate (for DS) than 2nd trimester screen Allows choice of CVS vs amniocentesis for dx. Safer termination choices avaialable. |
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Disadvantages of 1st trimester screening
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Requires NT measurement performed at a certified center
Does not screen for NTD's |
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What is integrated screening?
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Consists of 1st & 2nd trimester serum markers and NT measurements
Combine results are given in 2nd trimester after 2nd screen preformed |
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What are the benefits of integrated screening?
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highest sensitivity & lowest false positive rate.
approximately 90-96% detection for DS 1-2% false positive rate Allows screening for NTD's |
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Disadvantages of integrated screening
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Get results in 2nd trimester can only offer amnio for dx.
increased maternal anxiety while waiting. Later termination choices with higher risks |
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USN information
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uses sound waves to produce image
Can detect many (not all) cases of NTD NT and nasal bone (accompanies 1st trimester serum screening for DS) Fetal anatomy-18-20 wks- offered for significant family hx. of detectable structural defects or genetic sydromes for f/u of positive serum screens, for prenatal hx of known teratogens. Routine fetal anomaly screen still requires full disclosure to women that this is genetic screening. |
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USN advantages:
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Easy to access and perfomr
well accepted no know harm for 1-2 scans |
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USN disadvantages:
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Normal scan does not guarantee healthy baby
Many anomalies not 'visible' or seen Abnormal result does not always mean a problem Increases maternal anxiety with spurious findings. |
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Screening education points for women:
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These tests are screening and NOT diagnostic
Testing is optional, can decline testing after education regarding test A negative result does not guarantee a healthy baby A positive result does not mean there is a problem Dx testing offered for positive screen What she would do with a positive result? |
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Amniocentisis:
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Offered to all women > 35 y/o
Offered to all pregnant women with positive screen Best done @ 15-18 wks Does detect DS & NTD |
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CVS;
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Offered to all pregnant women > 35 y/o if they present early enough in first trimester
Best done between 10-12 wks Does NOT detect NTD Does detect DS Does allow for early termination |
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All pregnant women should be offered:
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DS/NTD/CF screening
Dx testing if > 35 y/o Full disclosure and informed consent for any of the above Option of NO testing Offered up to 20 wks |
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Prenatal genetic counseling required for:
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All pregnant women regarding DS and NTD options available
Advanced maternal age Abnormal serum marker screening results Fetal abnormalities on prenatal USN Personal of Family hx of a known or suspected genetic disorder, birth defect or chromosome abnormality. Family hx. of MR or unknown etiology Patient with a medical condition known or suspected to affect fetal development |
