The Principles of Clinical Cytogenetics - Extra Materials - Springer

300 Linda Marie Randolph
Table 13
Clinical Outcome of Second-Trimester Finding of Isolated Bright Hyperechoic Bowel
Scioscia a Nyberg b Bromley a Slotnick b Muller a MacGregor b
(205) (206) (208) (215) (210) (211)
1. No. of cases with 18 64 42 102 182 45
isolated bright HEB
2. No. of cases with 13 (72) 41 (75) 26 (62) — 111 (67) 34 (76)
normal outcome (%)
3. No. of cases with 2 c (11) 7 d (11) 0 5 e (4.9) 8 (4.5) 0/16 (0)
chromosome abnor. (%)
4. No. of cases with cystic 0 f /17 (0) NT b NT g 7/65 (11) 10/116 h (8.6) 2/15 (13)
fibrosis mutations (%)
5. No. of cases with NT g 1 (1.6) — — 7/? (?) 2/45 (4)
infections (%)
6. No. of cases with 1 (5.6) 6 (9.3) 8 (19) — 10/121 (8) NR i
IUGR (%)
7. No. of cases with 2 (11) 3 (4.7) 15 (36) — 24/104 (23) 3/45 (6.7)
nonelective demise (%)
Note: Excludes fetuses with ultrasound abnormalities other than isolated HEB.
a Retrospective study.
b Prospective study.
c Both trisomy 21.
d Five trisomy 21, one 47,XXX, one trisomy 13.
e All trisomy 21.
f Seven CF mutations tested.
g Not tested.
h One ∆F508 homozygote, nine heterozygotes; seven of the nine were unaffected, and the other two had no follow-up
information. One to eight mutations tested.
j Not reported.
that the low levels in CF might be the result of delayed passage of meconium, and in trisomy 18 and
21, the delayed passage might be the result of decreased bowel motility or abnormal meconium.
Fetuses with intra-amniotic bleeding have a to sevenfold increase in HEB (208,218). These investigators
hypothesized that swallowing of amniotic fluid containing heme pigments after intra-amniotic
bleeding seemed to be the cause of the echogenicity.
Other Ultrasound Markers of Aneuploidy
A summary of several series of ultrasound studies indicating risks of chromosome abnormalities
in association with specific ultrasound findings is shown in Table 14. Clearly, some ultrasound markers
in isolation indicate a significant risk of chromosome abnormality, and others might not achieve
significance unless other ultrasound abnormalities or other maternal risk factors are present.
In the past 15 years, medicine in the United States has evolved from recommending amniocentesis
to women 35 and older to refining risks based on a variety of ultrasound and maternal serum screening
markers. This has led to increased detection of chromosome abnormalities while not significantly
increasing the use of amniocentesis, as some women 35 and older now have their a priori risks
altered downward and choose not to have amniocentesis as a result. Several scoring indices have
been developed to provide individualized risk assessments (203,219–223). The fact is that anyone
with an ultrasound machine in the office can do an ultrasound examination, and the range of expertise
and resolution vary significantly among practitioners and machines. Optimally, each practitioner
should develop his or her own index based on the prospective evaluation of a large series of patients.
These indices will be much more valid in that practice than those derived from the literature.