Fetal brain asymmetry: in utero sonographic study of normal fetuses.
OBJECTIVE
The objective of the study was to evaluate the magnitude of normal fetal brain asymmetry.


METHODS
This was a prospective study. Normal fetuses between 19-28 weeks of gestation were studied. The cerebral atria, occipital cortex, and hemispheres in both sides were measured. The difference between each side was evaluated and was correlated with sex, head biometry, and estimated weight.


RESULTS
Four hundred six fetuses were studied. Mean atrial width was larger in the males and on the left side (5.2% and 6.5%, respectively). Mean cortical width was 2.6% larger in males but 5.5% thinner on the left side. Mean hemisphere width was larger in males and on the left side (2.3% and 1.5%, respectively). The atria and the cortex presented an inverse relationship regarding fetal growth parameters.


CONCLUSIONS
Brain asymmetry represents normal fetal brain developmental phenomena. It is sex dependent and lateralized in most cases to the left. Lateralization was more accentuated in males.
Kivilevitch
Zvi
Z
Ultrasound Unit, Maccabi Health Services, Beer Sheva, Israel.
Achiron
Reuven
R
Zalel
Yaron
Y
D001921:Brain / Q000033:anatomy & histology* / Q000196:embryology*; D002552:Cerebral Ventricles / Q000033:anatomy & histology / Q000196:embryology; D002831:Choroid Plexus / Q000033:anatomy & histology / Q000196:embryology; D004453:Echoencephalography / Q000706:statistics & numerical data*; D005260:Female; D007839:Functional Laterality; D005865:Gestational Age; D006801:Humans; D008297:Male; D015588:Observer Variation; D009778:Occipital Lobe / Q000033:anatomy & histology / Q000196:embryology; D011247:Pregnancy; D011446:Prospective Studies; D012016:Reference Values; D012727:Sex Characteristics; D017678:Sex Distribution; D016216:Ultrasonography, Prenatal / Q000706:statistics & numerical data*