Difference between revisions of "1st Trimester US"

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*Transvag when gestational sac (MGSD) equals 8mm
 
*Transvag when gestational sac (MGSD) equals 8mm
 
*Transabd when gestational sac (MGSD) equals 20mm
 
*Transabd when gestational sac (MGSD) equals 20mm
 +
*Yolk sac >6mm - recommend follow-up as most will result in failed pregnancy
  
  

Latest revision as of 18:52, 28 April 2011

Early preganancy embryo visualized
Early preganancy embryo not visualized
EarlyPregChart.jpg

Fetal Heart Beat

  • Should be detected if embryo is >5 mm (CRL) or >6 weeks.
  • Lower limit of normal is 90 bpm at 5-6 weeks or 120 bpm by 8 weeks
  • Normal during 2nd and 3rd trimester is 120-180 bpm


bHCG

  • Double every 48 hrs
  • At 2000 gestational sac should be seen


Mean Gestational Sac Diameter (MGSD)

  • Can be used to estimate gestational age when fetal pole not present
  • Caution "pseudogestational sac" seen with Ectopic pregnancy when don't see yolk sac


Yolk Sac should be visualized

  • Transvag when gestational sac (MGSD) equals 8mm
  • Transabd when gestational sac (MGSD) equals 20mm
  • Yolk sac >6mm - recommend follow-up as most will result in failed pregnancy


Fetal Pole should be visualized

  • Transvag when gestational sac (MGSD) equals 16mm
  • Transabd when gestational sac (MGSD) equals 25mm


Nonviable Pregnancy

  • Nonvisualization of a yolk sac with mean sac diameter of 13 mm
  • Nonvisualization of an embryo with mean sac diameter of 18 mm
  • Nonvisualization of cardiac activity with embryo of 5 mm in length


Nuchal Translucency


Corpus luteal cysts of pregnancy should resolve by 16 weeks.

Use the term embryo instead of fetus in first trimester.