Posterior brain in fetuses with trisomy 18, trisomy 13 and triploidy at 11 to 13 weeks' gestation.
OBJECTIVE
To measure changes in the posterior fossa of first-trimester fetuses with trisomy 18, trisomy 13 and triploidy.


METHODS
Brain stem (BS) diameter and BS to occipital bone (BSOB) diameter were measured in images of the midsagittal view of the face at 11(+0) to 13(+6) weeks from 45 trisomy 18, 21 trisomy 13 and 15 triploid fetuses and compared with values in 162 euploid fetuses.


RESULTS
In euploid fetuses BS and BSOB diameters increased significantly with crown-rum length and the BS to BSOB ratio decreased. In all three aneuploidies BSOB diameter was significantly higher than in euploid fetuses. In trisomy 18 and trisomy 13, the BS diameter and BS to BSOB ratio were decreased. The BS to BSOB ratio was below the 5(th) percentile in 16 (35.6%), 17 (81.0%) and 5 (33.3%) of trisomy 18, trisomy 13 and triploidy, respectively. In 7 (8.6%) of the aneuploid fetuses there was open spina bifida and in all these cases the BS to BSOB ratio was above the 95(th) percentile.


CONCLUSIONS
At 11 to 13 weeks' gestation many fetuses with trisomy 18, trisomy 13 and triploidy have measurable abnormalities in the posterior brain.
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
Ana Fatima A
AF
Ferreira
Argyro
A
Syngelaki
Anna
A
Smolin
Ana-Maria
AM
Vayna
Kypros H
KH
Nicolaides
D000328:Adult; D001921:Brain / Q000196:embryology; D001933:Brain Stem / Q000000981:diagnostic imaging / Q000196:embryology; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D003388:Cranial Fossa, Posterior / Q000000981:diagnostic imaging* / Q000196:embryology; D004453:Echoencephalography / Q000379:methods; D005260:Female; D047109:Fetal Development / Q000235:genetics / Q000502:physiology; D005333:Fetus / Q000033:anatomy & histology / Q000196:embryology; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000235:genetics / Q000502:physiology; D057885:Triploidy; D014314:Trisomy / Q000175:diagnosis / Q000235:genetics; D016216:Ultrasonography, Prenatal / Q000379:methods