[Early transvaginal measurement of cephalic index for the detection of fetuses at risk for Down syndrome].
BACKGROUND
The aim of this study was to evaluate the utility of cephalic index screening in early pregnancy for the identification of fetuses at risk for trisomy 21.


METHODS
Measurements of cephalic index, calculated as the ratio between biparietal diameter/occipito-frontal diameter, were obtained in 36 Down syndrome fetuses and the values were compared with normal data in the same gestational periods considered.


RESULTS
Cephalic index was found to show fairly constant values throughout the period evaluated. The measurements obtained in Down syndrome fetuses were similar to those obtained in euploid fetuses.


CONCLUSIONS
The data obtained show that in early pregnancy cephalic index cannot be considered a useful tool in the detection of fetuses at risk for Down syndrome.
Istituto di Clinica Ostetrica e Ginecologica, Università Cattolica del Sacro Cuore, Rome, Italy.
L
L
Guariglia
P
P
Rosati
D002508:Cephalometry / Q000379:methods*; D003430:Cross-Sectional Studies; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D005865:Gestational Age; D006257:Head / Q000196:embryology; D006801:Humans; D011247:Pregnancy; D011296:Prenatal Diagnosis; D016216:Ultrasonography, Prenatal