in the name of god first trimester screening dr.m.moradi

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In the name of In the name of god god First Trimester Screening Dr.M.Moradi

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  • In the name of god First Trimester Screening

    Dr.M.Moradi

  • First Trimester ScreeningA method to identify women at risk for having an aneuploid fetus from the general populationAlso can identify other birth defects such as congenital heart defects and diaphragmatic hernia Performed during 11-14 weeks gestationPatient Preferences and earlier diagnosis/ reassurance

  • All patients have a 2% to 3% risk of birth defects, regardless of their prior history, family history, maternal age, or lifestyle.Chromosome abnormalities account for approximately 10% of birth defects.

  • A detailed fetal anatomic survey performed at 18 to 22 weeks remains the primary means for detecting the majority of serious structural birth defects.first-trimester screening at 11 to 14 weeks has developed into the initial screening test for many patients.

  • The primary advantage of first trimester screening is earlier diagnosis of abnormalities (or early reassurance of the anxious patient), with the option of an earlier and safer pregnancy termination.

  • Advantages of 1st Trimester ScreeningInformation earlier, more optionsReduce number of invasive proceduresMay identify other severe anomalies (or risk for) at time of scan and increased risk of adverse pregnancy outcomereferral for 2nd evals.Good time to date pregnancy accurately NT good for multiple gestation

  • First Trimester Screening GOALS of this screen: To increase sensitivity, decrease false-positive ratesTo decrease number of unnecessary invasive prenatal diagnosis tests.NOT to increase number of elective abortions.U/S measurements (NT) and free B-hCG, PAPP-A

  • Use of the guidelines proposed by the Fetal Medicine Foundation have resulted in a high consistency in results

  • Nuchal translusency

  • HistoryDr.langdon Down 18661980s1992..prof Nicolaid.Normal range?Mechanism?Normal Karyotype with increased NT

  • The mechanism for increased NT may vary with the underlying condition. The most likely causes include heart strain or failure and abnormalities of lymphatic drainage . Evidence for heart strain includes the finding of increased levels of atrial and brain natriuretic peptide mRNA in fetal hearts among trisomic fetuses

  • Nuchal Translucency

    Measurements must be performed by certified individual!

  • True sagitalPositionCaliperSeparation of amnionmagnification

  • The normal range for NT measurements is gestational age dependent. the median NT increases from 1.3mm at a crown-rump length (CRL) of 38 mm to 1.9 mm at a CRL of 84 mm.

    The 95th percentile increases from 2.2 mm at a crown rump length of 38 mm to 2.8 mm at a CRL of 84 mm.

  • The ability to measure NT and obtain reproduciblen results improves with training; good results are achieved after 80 and 100 scans for the transabdominal and the transvaginal routes, respectively

  • screeningBasicNTBIOCHEMISTRY Advanced

  • The two most effective maternal serum markers currently used in the first trimester are pregnancy-associated plasma protein A (PAPPA)and free B-human chorionic gonadotrophin(B-hCG).

    Maternal serum free b-human chorionicgonadotropin (b-hCG) normally decreases withgestation after 10 weeks and maternal serumPAPP-A levels normally increase.

    Levels of these two proteins tend to be increased and decreased, respectively, in pregnancies affected by trisomy 21.

  • PAPP-A and Free B-hCGOn average, baby with trisomy 21 will have 2.0 Mom for B-hCG and 0.4 MoM PAPP-A

  • Basic screeningHigh risk 1/50Moderate riskLow risk 1/1ooo

  • AdvancedNasal boneFacial angleDuctus venosusTricuspid regurgitation

  • Professor Kypros Nicolaides.

  • The fetal nasal bone can be visualized by sonography at 1113+6 weeks of gestation (Cicero et al 2001). Several studies have demonstrated a high association between absent nasal bone at 1113+6 weeks and trisomy 21, as well as other chromosomal abnormalities.

  • Three line

  • Fronto maxillary angle

  • GA dependentCRL=45mm, 84CRL=84mm, 76Above 95% for age=increased risk of trisomy

  • Ductus venosus

  • Sample sizeAngle Filter sweep speed

  • Tricuspid regurgitation

  • Fetal heart rate

    In normal pregnancy, the fetal heart rate (FHR) increases from about 100 bpm at 5 weeks of gestation to 170 bpm at 10 weeks and then decreases to 155 bpm by 14 weeks. At 1013+6 weeks, trisomy 13 and Turner syndrome are associated with tachycardia, whereas in trisomy 18 and triploidy there is fetal bradycardia (Figure 5; Liao et al 2001). In trisomy 21, there is a mild increase in FHR.

  • Urinary bladder

  • In first trimester>7mm=megacystitis7-15 mm..>15mm