Human prenatal nasal bone lengths: normal standards and length values in fetuses with cleft lip and cleft palate

The aim of this study was to present prenatal autopsy standards for nasal bone length in normal fetuses, as well as to compare nasal bone lengths in human fetuses with cleft lip and palate with those standards.

The material consisted of human fetuses investigated in connection with diagnosed and legally approved abortions and spontaneous abortions; 40 were normal and 26 had cleft lip and palate (7 isolated cleft lip, 12 isolated cleft palate, and 7 combined cleft lip and palate). Menstrual ages (MA) ranged from 12 to 25 weeks, crown-rump length (CRL) from 55 to 210 mm and foot length (FL) from 7 to 44 mm. All fetuses were radiographed in lateral projection, and, using these images, the nasal bone lengths were measured with a digital caliper. Regression analyses were performed.

Standards for normal nasal bone length at different ages are expressed as menstrual age, crown-rump length, or foot length. Comparisons with normal standards showed that the isolated cleft lip group had a significantly smaller nasal bone length than the normal fetuses had. Fetuses with isolated cleft palate and fetuses with combined cleft lip and palate showed no significant deviation from normal standards.

Normal nasal bone standards can contribute to information on deviations in nasal bone length for aborted fetuses with known and unknown genotypes. The differences in nasal bone lengths in fetuses with different lip and palate clefting can contribute to understanding the pathogenesis of cleft lip and palate.