To investigate the clinical implications of two categories of fetal bilateral cleft lip and palate (BCLP): with premaxillary protrusion and with a flattened profile. This was a retrospective study of fetuses with a prenatal diagnosis of BCLP at the Department of Obstetrics and Gynecology of the University of Bologna in the period 1991-2005. BCLP was diagnosed prenatally in 14 cases (mean gestational age at diagnosis, 21 (range, 12-36) weeks). In nine of these, there was a premaxillary pseudomass; in the remaining five, the profile was flat. Associated structural and/or chromosomal anomalies were found in two of the nine with a premaxillary pseudomass and in all five of those with a flat profile (P = 0.02). All fetuses with a flat profile had aneuploidies (three trisomy 18, one trisomy 13, one trisomy 8 mosaic), as did one of the nine with a premaxillary pseudomass. Eight of the pregnancies were terminated, including three of those with a premaxillary pseudomass and all five of those without. All continuing pregnancies resulted in live births, although one neonate affected by Krabbe's disease died shortly after birth. Our findings suggest that a third of cases of BCLP diagnosed in utero have a flat profile and these are at high risk of lethal aneuploidies.