ultrasound diagnosis of fatal anomalies

16 Growth Disturbance
Macrosomia
Definition: Birth weight above 4000 g or estimated
fetal weight above the 95th centile for the
given gestational age. It is important to differentiate
between a constitutionally large fetus
(“large for gestational age”) and a fetus with
characteristic diabetic macrosomia (normal
head circumference, increase in abdominal circumference,
increased subcutaneous fat tissue).
Procedure after birth: A pediatrician should be
present at delivery. Fetal distress and hypoglycemia
are often observed.
Prognosis: Normal, unless there are complications
and injuries arising from delivery (for example,
shoulder dystocia).
Incidence: 1–2% of births; if the percentile
curves were correct, 5% of births would be detected.
Clinical history: Genetically determined; parental
heights. Pathological glucose tolerance test.
Gestational diabetes. Macrosomia occurs
frequently in consecutive pregnancies.
Associated syndromes: Macrosomia is seen in
Beckwith–Wiedemann syndrome, Weaver syndrome,
and Sotos syndrome.
Ultrasound findings: Fetal parameters, mainly
the abdominal circumference, lie above the 95th
centile. Estimating fetal weight, especially in
macrosomia, is relatively inaccurate (maximum
sensitivity 70%, positive predictive value 60 %).
The abdominal circumference is possibly the
best parameter for detecting macrosomia. The
quotient of femur length and abdominal circumference
(normally 20%) is not a reliable
parameter either (sensitivity 60%). Mild hydramnios
is frequently present. Typically, the
neck region and cheeks (cheek-to-cheek distance
as measured using Abramowicz’s method)
appear swollen, but this is due to fat tissue rather
than edema.
Clinical management: Glucose tolerance test,
serial ultrasounds, possibly early delivery at
38 weeks of gestation. If the estimated fetal
weight is above 4500 g, the benefit of primary
cesarean section to avoid shoulder dystocia is
disputed, as weight estimation in macrosomia is
frequently not very accurate.
References
Benson CB, Coughlin BF, Doubilet PM. Amniotic fluid
volume in large-for-gestational-age fetuses of nondiabetic
mothers. J Ultrasound Med 1991; 10: 149–
51.
Best G, Pressman EK. Ultrasonographic prediction of
birth weight in diabetic pregnancies. Obstet Gynecol
2002; 99: 740–4.
Delpapa EH, Mueller HE. Pregnancy outcome following
ultrasound diagnosis of macrosomia. Obstet Gynecol
1991; 78: 340–3.
Elliott JP, Garite TI, Freeman RK, McQuown DS, Patel IM.
Ultrasonic prediction of fetal macrosomia in diabetic
patients. Obstet Gynecol 1982; 60: 159–62.
Landon MB, Mintz MC, Gabbe SG. Sonographic evaluation
of fetal abdominal growth: predictor of the
large-for-gestational-age infant in pregnancies complicated
by diabetes mellitus. Am J Obstet Gynecol
1989; 160: 115–21.
Levine AB, Lockwood CJ, Brown B, Lapinski R, Berkowitz
RL. Sonographic diagnosis of the large for gestational
age fetus at term: does it make a difference? Obstet
Gynecol 1992; 79: 55–8.
Lurie S, Zalel Y, Hagay ZJ. The evaluation of accelerated
fetal growth. Curr Opin Obstet Gynecol 1995; 7: 477–
81.
Miller JMJ, Brown HL, Khawli OF, Korndorffer FA, Gabert
HA. Fetal weight estimates in diabetic gravid women.
JCU J Clin Ultrasound 1988; 16: 569–72.
Miller JMJ, Kissling GE, Brown HL, Nagel PM, Korndorffer
FA, Gabert HA. In utero growth of the large-formenstrual-age
fetus. JCU J Clin Ultrasound 1989; 17:
15–7.
Taylor R, Lee C, Kyne-Grzebalski D, Marshall SM, Davison
JM. Clinical outcomes of pregnancy in women
with type 1 diabetes (1). Obstet Gynecol 2002; 99:
537–41.
Van Assche FA, Holemans K, Aerts L. Long-term consequences
for offspring of diabetes during pregnancy
[review]. Br Med Bull 2001; 60: 173–82.
Wong SF, Chan FY, Cincotta RB, Oats JJ, McIntyre HD.
Sonographic estimation of fetal weight in macrosomic
fetuses: diabetic versus non-diabetic pregnancies.
Aust N Z J Obstet Gynaecol 2001; 41: 429–
32.
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