Delayed structural development in an acardiac fetus: an echographic observation.
BACKGROUND
Twin reversed arterial perfusion (TRAP) is a rare condition in monozygotic multiple gestations, caused by the formation of large arterio-arterial anastomoses. Only few serial ultrasound observations are reported, showing the delayed development in the recipient twin.


METHODS
A monochorionic monoamniotic twin pregnancy with discordant growth was diagnosed at 11 weeks and 4 days in a 28-year-old primigravida. The smaller twin, who first appeared as an amorphic mass, showed growth and developed a clearly recognizable spine and lower limbs in further ultrasound examinations.


CONCLUSIONS
This case illustrates that developmental arrest in acardiac fetuses does not affect the total organism at one time, but that some embryonic fields keep on developing into macroscopically recognizable structures.
Van Gaever
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C
Department of Obstetrics and Gynaecology, Ghent University Hospital, Ghent, Belgium. cathy_vangaever@hotmail.com
Defoort
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P
Dhont
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M
D000328:Adult; D004200:Diseases in Twins / Q000000981:diagnostic imaging*; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D005318:Fetal Heart / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005333:Fetus / Q000002:abnormalities; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011272:Pregnancy, Multiple; D014430:Twins, Monozygotic; D016216:Ultrasonography, Prenatal / Q000379:methods*