>Dani: What's the difference between a regular ultrasound and
>a Levil II ultrasound? (You make lots of good points, and
>maybe I should revisit this issue. My doc seemed a little
>surprised that I may not want to have it done, so most of her
>patients must have the screening done...)
You would usually have this done at your 20 week appt.
Here's some info on Level II U/S:
A Level 2 Ultrasound, also called a targeted ultrasound, is conducted specifically to look for particular markers based upon what was found in the initial ultrasound or triple screen. Perhaps the initial ultrasound found a choroid plexus cyst or the baby is small for gestational age. Or perhaps a triple screen result indicated higher than normal odds for a chromosomal condition. In those cases, a level 2 ultrasound is often recommended. This is another screening test that does not diagnose Trisomy 18 but gives more information about the odds of its presence.
A perinatologist, fetal medicine specialist, or someone else who specializes in high-risk pregnancies and who is trained to look for the markers of chromosomal disorders typically conducts level 2 ultrasounds. These markers are soft markers and structural markers. Soft markers are characteristics frequently seen on babies with the disorder, and structural markers are abnormalities in organ and bone formation.
Some of these markers for Trisomy 18 are as follows:
clenched hands, choroid plexus cysts, rocker bottom feet, delayed growth, heart defects such as VSD, ASD, and coarctation, kidney abnormalities, omphalocele, esophageal atresia, and polyhydramnios (excess amniotic fluid)
What is meant by a Level II ultrasound examination?
Answer:
A level II ultrasound examination refers to a 'targeted' examination. This is usually performed at a perinatal center where more expertise in ultrasound scanning is available. Situations when a level II scan is ordered include:
suspected fetal anomaly during a level I examination, severe IUGR, elevated maternal-serum AFP, Oligohydramnios, polyhydramnios, two-vessel umbilical cord detected at the level I examination, fetal cardiac arrhythmia, and exposure to drugs or chemicals in the first trimester....etc. Detailed scanning for any congenital anomalies and growth abnormalities is done on top of the basic documentations obtained at the level I examination, which refers to:
in the first trimester,
a. documentation of the location of the gestational sac.
b. documentation of the crown-rump length.
c. documentation of the presence or absence of fetal life.
d. evaluation of the uterus (including cervix) and adnexa.
in the second and third trimester,
a. documentation of fetal life, number, and presentation.
b. documentation of an estimate of amniotic fluid volume.
c. documentation of placental location.
d. documentation of gestational age. Assessment of the BPD, FL, AC and othe fetal parameters.
e. documentation of basic fetal anatomy (including a basic 4 chamber view of the heart, spine, stomach, kidneys, bladder, umbilical cord insertion ... etc ).
One should not not dwell too much on the definitions or guildlines for a level II ultrasound scan. In a level II scan the sonologist should try as hard as he can to look for and assess any abnormality that is present in the fetus. It's meaningless to be thinking about level III or even level IV scans.
