Frontomaxillary facial angle measurements in euploid Korean fetuses at 11 weeks' to 13 weeks 6 days' gestation.
OBJECTIVE
The purpose of this study was to evaluate the distribution of fetal frontomaxillary facial angles in a euploid Korean population at 11 weeks' to 13 weeks 6 days' gestation.


METHODS
Three-dimensional volumes of the fetal head were obtained from women with low-risk singleton pregnancies at 11 weeks' to 13 weeks 6 days' gestation who consented to this prospective study. Only fetuses with either a normal karyotype confirmed by amniocentesis or no abnormalities after delivery were considered eligible for analysis and were characterized as euploid for the purposes of this study. Women with multiple pregnancies and those who were lost to follow-up and fetuses with abnormal karyotypes or anomalies diagnosed in utero or postnatally were excluded. The frontomaxillary facial angle was measured twice offline by a single examiner. Cases were categorized by crown-rump length (CRL) in 10-mm intervals for analysis of the frontomaxillary facial angle.


RESULTS
Among 375 enrolled cases, 158 were eligible for frontomaxillary facial angle analysis. The overall mean frontomaxillary facial angle ± SD was 88.6° ± 9.7°. The mean frontomaxillary facial angle for fetuses with a CRL of 40 to 49 mm (n = 35) was 93.7°; 50 to 59 mm (n = 53), 92.6°; 60 to 69 mm (n = 36), 85.3°; and 70 to 79 mm (n = 34), 81.0°, showing an inverse relationship between the mean frontomaxillary facial angle and CRL (r = -0.5334; P < .0001). The proportion of cases with frontomaxillary facial angles of 85° or greater was 60.8%, and that of cases with angles of 90° or greater was 37.3%.


CONCLUSIONS
Ethnic differences in frontomaxillary facial angle measurements should be considered when incorporating the frontomaxillary facial angle in fetal aneuploidy screening in the Korean population.
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Yonsei University Health System, 134 Shinchon-dong, Seodaemun-gu, Seoul, Korea.
Sun Rye
SR
Jeon
Hyung Min
HM
Choi
Young Ho
YH
Roh
Young Han
YH
Kim
Ga Hyun
GH
Son
Ka Hyun
KH
Nam
Yong Won
YW
Park
Ja-Young
JY
Kwon
D000328:Adult; D018568:Crown-Rump Length; D005145:Face / Q000000981:diagnostic imaging* / Q000196:embryology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D056910:Republic of Korea / Q000208:ethnology; D018709:Statistics, Nonparametric; D016216:Ultrasonography, Prenatal / Q000379:methods*