Frontal space distance in facial clefts and retrognathia at 11-13 weeks' gestation.

OBJECTIVE: To examine the frontal space (FS) distance in first-trimester fetuses with bilateral, unilateral or median cleft lip and palate and in those with retrognathia. METHODS: This was a retrospective study using stored two-dimensional ultrasound images of fetal profiles that were recorded at the time of the nuchal translucency (NT) scan at three prenatal medical centers. Images of 300 normal fetuses and 53 fetuses with facial defects were obtained. To measure the FS distance, a line was drawn between the anterior edge of the mental protuberance of the mandible and anterior edge of the maxilla (MM line) and extended upwards in front of the forehead. The perpendicular distance (FS distance) between the MM line and the skin at the point of largest excursion of the fetal forehead was measured. In cases in which the MM line was located anteriorly to the forehead, the distance was measured in the same fashion but was multiplied by -1. Two operators measured the FS distance twice, independently of each other. FS distances were transformed into Z-scores based on the linear relationship with crown-rump length (CRL) in normal fetuses. The distribution of FS distances in fetuses with bilateral, unilateral or median cleft lip and palate and those with retrognathia were compared with that in the normal group using Student's t-test. RESULTS: A search of the centers' databases identified 53 abnormal cases including 20, nine and eight with a bilateral, unilateral and median cleft lip and palate, respectively, and 16 cases of retrognathia. In fetuses with bilateral, unilateral and median clefts and those with retrognathia, median delta NT was 1.00 mm, 0.37 mm, 4.00 mm and 0.26 mm, respectively. Among these affected groups, 12 (60.0%), six (66.7%), two (25.0%) and eight (50.0%) fetuses had an abnormal karyotype. In the normal population, FS distance was dependent on CRL measurement (FS = 6.62 - (0.08 × CRL); r = -0.539; P < 0.0001). In fetuses with a bilateral and median cleft and in those with retrognathia, FS distance was significantly different from that in the normal population (all P < 0.0001), however, the difference was not significant in fetuses with unilateral clefts (P = 0.103). The respective Z-scores of FS distance for fetuses with bilateral, unilateral and median clefts and retrognathia were -9.7 ± 2.0, -3.1 ± 5.1, 8.2 ± 3.4 and -7.3 ± 2.3. Measurements were ≥ 99(th) and ≤ 1(st) centiles in all but one (98.1%) case. CONCLUSION: The FS distance appears to be a helpful tool in the detection of facial clefts at 11-13 weeks' gestation. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

The frontal space measurement in euploid and aneuploid pregnancies at 11-13 weeks' gestation.

OBJECTIVE: The aim of this study is to evaluate whether the measurement of the frontal space (FS) improves first trimester combined aneuploidy screening. METHODS: We have presented a retrospective study including 2D images of the nuchal translucency measurement of 300 euploid and 133 trisomic fetuses that were seen at the prenatal department at the University of Tuebingen, Germany. For the FS measurement, a mandibulo-maxillary line (MML) was created by connecting the anterior edge of the mental protuberance and anterior edge of the maxilla. The MML was then extended upwards. A measurement was taken perpendicular from the MML to the skin line over the point of largest excursion of the fetal forehead. After transformation into z-scores based on the crown rump length, the FS distribution in fetuses with trisomy 21, 18, and 13 was compared with the euploid group by using a student's t-test. RESULTS: The mean FS in euploid fetuses was 1.25 mm. In fetuses with trisomy 21, 18, and 13, the mean FS measurements were 2.96, 3.22, and 2.03 mm. In euploid and trisomy 21, 18, and 13 pregnancies, FS measurements were above the 95th centile in 5.3%, 41.1%, 34.3%, and 12.5% of the cases. The mean z-scores were significantly higher in trisomy 21 and 18. CONCLUSION: First trimester FS measurement may improve first trimester combined screening.

Frontomaxillary facial angle in fetuses with spina bifida at 11-13 weeks' gestation.

OBJECTIVE: To determine whether in fetuses with open spina bifida at 11-13 weeks' gestation the frontomaxillary facial angle is decreased. METHODS: The frontomaxillary facial angle was measured in 20 fetuses with open spina bifida and in 100 normal controls matched for crown-rump length (CRL) at 11 + 0 to 13 + 6 weeks and the values in the two groups were compared. RESULTS: In the control group the frontomaxillary facial angle decreased significantly with CRL from a mean of 84.0 degrees at a CRL of 45 mm to 76.5 degrees at a CRL of 84 mm (SD, 3.26 degrees). In the spina bifida group the mean frontomaxillary facial angle, corrected for CRL, was 9.9 degrees lower than in the controls and it was below the 5(th) centile in 18 (90%) of the cases (P < 0.0001). CONCLUSIONS: In fetuses with open spina bifida at 11-13 weeks' gestation the frontomaxillary facial angle is decreased and this measurement may be useful in early screening for this abnormality.

Frontomaxillary facial angle in trisomy 21 fetuses at 16-24 weeks of gestation.

OBJECTIVES: To establish a normal range for the frontomaxillary facial (FMF) angle by three-dimensional (3D) ultrasound imaging and to examine the FMF angle in trisomy 21 fetuses at 16-24 weeks of gestation. METHODS: We measured the FMF angle using 3D volumes of the fetal profile obtained with the transducer parallel to the long axis of the nose and at 45 degrees to the palate, which had been acquired from 150 normal fetuses and 23 fetuses with trisomy 21. RESULTS: In the normal group there was no significant association between the FMF angle and gestational age; the mean FMF angle was 83.9 degrees (range, 76.9-90.2 degrees ) and the 95(th) centile was 88.5 degrees . In 15 (65.2%) of the fetuses with trisomy 21 the FMF angle was greater than 88.5 degrees . Repeatability studies demonstrated that in 95% of cases the difference between two measurements of FMF angle by the same operator and different operators was less than 5 degrees . CONCLUSIONS: In the majority of second-trimester fetuses with trisomy 21 the FMF angle is increased.

Frontomaxillary facial angle in fetuses with trisomy 21 at 11-13(6) weeks.

OBJECTIVE: The objective of the study was to investigate the location of the front of the maxilla in relation to the forehead in fetuses with trisomy 21 at 11-13 weeks of gestation. STUDY DESIGN: A three-dimensional volume of the fetal head was obtained before karyotyping in 100 fetuses with trisomy 21 and 300 euploid fetuses. The frontomaxillary facial (FMF) angle, defined as the angle between the upper surface of the upper palate and the frontal bone in a midsagittal view of the fetal face, was measured. RESULTS: The FMF angle was significantly larger in the trisomy 21 than in the euploid fetuses (mean 88.7 degrees, range 75.4-104 degrees vs mean 78.1 degrees, range 66.6-89.5 degrees, P < .001). The FMF angle was more than 85 degrees in 69% of the trisomy 21 fetuses and in 5% of the euploid fetuses. There was no significant association between the FMF angle and nuchal translucency thickness. CONCLUSION: Measurement of FMF angle is likely to be a useful adjunct in screening for trisomy 21.

Growth of the fetal forehead and normative dimensions developed by three-dimensional ultrasonographic technology.

Sonographic imaging of the fetal face is important since a number of chromosomal aberrations are associated with facial malformations. In the past, imaging of the fetal forehead and diagnosis of frontal bossing had been based on subjective evaluation using two-dimensional ultrasonography. The purpose of this study was to evaluate quantitatively the fetal forehead using three-dimensional technology to generate normative data throughout gestation. This should allow the objective diagnosis of abnormal growth of the fetal forehead, such as frontal bossing. We also report a case of a fetus with frontal bossing in whom the generated nomogram was applied. A cross-sectional study was performed in 130 normal healthy singleton pregnancies between 16 and 38 weeks' gestation. Using three-dimensional ultrasonography, a line connecting the apex of the philtrum and the nasion was drawn across the anterior forehead, which delineated the area of the forehead for analysis. The forehead length, forehead height, and forehead area under the curve were measured and the forehead index was calculated. A second order polynomial growth function was noted throughout gestation for the forehead length (r = 0.93), forehead height (r = 0.97), and forehead area (r = 0.97). The fetal forehead index remained relatively constant throughout gestation. The results of this study provide normative data of fetal forehead length, width, and area using three-dimensional ultrasonographic technology. Normative dimensions of the fetal forehead developed and presented herein are expected to serve as a basis for the objective assessment of presumed fetal facial abnormalities and may facilitate the detection of the associated syndromes. This is demonstrated in our case report of an achondroplastic fetus in whom all forehead dimensions were above the 95th percentile.