Biophysical Screening and Soft Markers in Ultrasound

Biophysical Screening

• Ultrasound biophysical screening includes fetal echo, MRI, ultrasound, nuchal translucency, soft markers, and mid-pregnancy scan.

Soft Markers

• Definition: Sonographic findings of uncertain significance that are nonspecific, often transient, and associated with normal fetuses but carry an increased risk for fetal aneuploidy.
• Include: nuchal translucency, ventriculomegaly, renal pelvic dilatation, echogenic bowel, facial clefting, small fetal biometry, choroid plexus cyst, skull shape, echogenic foci, and two vessels umbilical cord.

Nuchal Translucency (NT)

• Definition: Sonographic measure of the amount of fluid at the back of the fetal neck.
• Increased risk of underlying abnormality with increased degree of dilatation.
• Normal NT: 1.8 mm, 6 mm, or 9 mm.
• Causes of increased NT: aneuploidy (especially trisomy 21), pulmonary hypoplasia, cardiac anomalies, diaphragmatic hernia, hydrocephalus, twin complications, and may be normal.

Echogenic Bowel

• Definition: Sonographic feature of bright bowel with echogenicity similar to adjacent bone.
• Causes of echogenic bowel: aneuploidy (especially trisomy 21), bleeding in amniotic fluid, bowel obstruction, cystic fibrosis, infection, and IUGR (intrauterine growth restriction).

Facial Cleft

• Definition: Deformities of the face and head that affect both bones and soft tissues.
• Formed in utero when normal development of a baby's head and neck are disrupted and parts of the face fail to fuse together.
• The most common is: cleft lip and cleft palate.

Choroid Plexus Cyst

• Definition: A little area of the choroid plexus blocks, causing the CSF to accumulate and form a cyst.
• A common finding and not considered an abnormality.
• These cysts are almost always gone by 34 weeks of pregnancy and occasionally persist in otherwise healthy babies.

Two Vessels Umbilical Cord

• Definition: The umbilical cord is the vital connection between the fetus and the placenta.
• May represent edema.
• A soft marker for Down syndrome.
• Timing: 11-14 weeks of pregnancy, at crown rump length (CRL) = 45-84mm.
• Normal: 6mm.

Ventriculomegaly

• Definition: A condition in which the ventricles appear larger than normal on a prenatal ultrasound.
• Ventricles are enlarged due to build up of CSF.
• Normal fetal brain: mild ventriculomegaly, ventriculomegaly, and ventriculomegaly.

Renal Pelvis Dilatation

• Definition: The area at the center of the kidney where urine collects and is funneled into the ureter, then to the bladder.
• Fetal renal pelvis dilatation is identified in 1% to 5% of pregnancies and is often a transient, normal variant.
• Normal: the umbilical cord has two arteries and one vein.