DVP < 2 cm	Oligohydramnios  singleton or twin
DVP ≥ 8 cm	Polyhydramnios singleton or twin Characterized as mild (8–11 cm), moderate (12–15 cm), or severe (≥16 cm)
AFI  ≥24 cm	Polyhydramnios in singleton Characterized as mild (24.0-29.9 cm), moderate (30.0- 34.9 cm), or severe (≥ 35 cm)
MCA PSV ≥ 1.5  MoM	Increased likelihood of fetal anemia
Cerebroplacental Doppler ratio (CPR) less than 1.08	Increased risk for adverse perinatal outcomes in growth-restricted fetus
FL to abdominal circumference (AC) ratio <0.16	Increased likelihood of  lethality in skeletal dysplasia
Inferior facial angle less than 49°	Increased likelihood of micrognathia
Jaw index less than 23	100% sensitivity and 98.1% specificity in diagnosing micrognathia
*Fetal HC  ≥ 3 SD below the mean for gestational age	Fetal microcephaly
*Fetal HC is ≥ 5 SD below the mean for gestational age	Pathologic microcephaly is considered certain
Atrial diameter of the lateral ventricle  ≥ 10 mm	Fetal cerebral ventriculomegaly Characterized as mild (10–12 mm), moderate (13–15 mm), or severe (>15 mm)

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