Zeng Xun, Li Xiaohong, Qin Lang, Huang Wei, Jin Song, Yu Haiyan
Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University.
Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China.
Medicine (Baltimore). 2020 Oct 2;99(40):e22558. doi: 10.1097/MD.0000000000022558.
During ultrasound prenatal screening, absence of the fetal nasal bone is used as a marker for common aneuploidies in singleton pregnancies. However, its application in multiple pregnancies is less sensitive and more challenging owing to difficulties in obtaining adequate views of the fetal face.
A 38-year-old woman with dichorionic-diamniotic (DCDA) pregnancy and a history of in vitro fertilization and embryo transfer was referred to our hospital with the absence of the nasal bone noted on ultrasound images obtained during the second trimester in 1 fetus.
Prenatal sonographic examination revealed the absence of the nasal bone in 1 fetus in the DCDA gestation. Amniocentesis performed on the dual amniotic sacs revealed normal karyotypes for each twin. The absence of the nasal bone was confirmed on a radiograph obtained postnatally in 1 infant.
The mother underwent routine outpatient care according to the gestational age and successfully delivered following lower-segment cesarean section.
Two live infants were uneventfully delivered. Radiography confirmed the absence of the nasal bone in 1 of the newborns on postnatal day 3. The infants were followed up until 2 years and 9 months of age, which revealed normal appearance and eating and breathing functions.
Prenatal diagnosis of the absence of nasal bone in 1 fetus of DCDA pregnancy has rarely been reported. Although a fetus with the absence of the nasal bone in DCDA gestation poses a significant risk of aneuploidy, it is acceptable when the defect is an isolated anomaly after ruling out genetic abnormalities. Appropriate consultation should be provided for these patients.
