Relationship between absent or hypoplastic fetal nasal bone and chromosome abnormalities: analysis of 187 cases / 中华围产医学杂志

ABSTRACT

Objective To investigate the relationship between absent or hypoplastic fetal nasal bone and chromosome abnormalities.Methods From January 2010 to April 2014,187 fetuses were found to have absent or hypoplastic nasal bone by prenatal ultrasound scanning in Guangzhou Maternal and Children's Hospital.All the pregnant women should undergo interventional prenatal diagnosis for fetal chromosome abnormalities,and should be followed up for three months after the expected delivery date.The correlation between absent or hypoplastic fetal nasal bone and chromosome abnormalities,and the effects of complicating structural defects were analyzed by descriptive analysis and the Chi-square test.Results Of the 187 pregnant women,126 underwent interventional prenatal diagnostic tests,and fetal chromosome abnormalities were detected in 36 cases (28.6％),including 26 cases (20.6％) of trisomy 21,6 cases (4.8％) of trisomy 18,three cases (2.4％) of trisomy 13 and one sex chromosome chimerism.In the 126 cases received prenatal diagnosis,the incidence of chromosome abnormalities in fetuses without other structural defects was significantly lower than that with structural defects [12.7％ (8/63) vs 44.4％ (28/63),x2=15.556,P=0.000].Among 63 cases without other structural defects,seven fetuses were confirmed to have chromosome abnormalities in 14 women with high risk by Down syndrome screening,no chromosome abnormalities were found in 39 pregnant women with low risk by Down syndrome screening,and one sex chromosome chimerism was found in the other ten women who did not undergo Down syndrome screening.Absent or hypoplastic nasal bone detected in the first trimester resulted in a higher risk of chromosome abnormalities than that detected in the second and the third trimester [25.5％ (28/110) vs 10.4％ (8/77),x2=6.613,P=0.007].Conclusions When a fetus is found to have absent or hypoplastic nasal bone,it is necessary to perform Down syndrome screening and a detailed morphology scan.Women shown to have fetuses with absent or hypoplastic nasal bone with other structural defects or high risk by Down syndrome screening should undergo prenatal diagnostic tests to exclude fetal chromosome abnormalities.