Prenatal diagnosis for trisomy 18——analysis of 9 cases

Objective To assess the effectiveness of prenatal screening with maternal serum markers and the sonographic characteristics of the foetus for detecting trisomy 18. Methods Amniotic fluid or the fetal blood samples were obtained and cultured in women with positive results in serum screening (n=36) and with abnormal findings in sonography (n=92) at 18~32 weeks of gestation, and then fetal karyotyping was performed. Results Nine cases of trisomy 18 and 2 cases of other abnormal karyotype were found among the 128 pregnant women (8.59%, 11/128). Four cases were diagnosed as trisomy 18 among the 36 women with positive screening results. The rate of abnormal karyotype among those women with abnormal sonographic findings was 7.61%(7/92,5 cases of trisomy 18 and 2 cases of other abnormal karyotype). Two cases of trisomy 18 had both positive result in screening and abnormality in sonography. Conclusions Prenatal screening for maternal serum markers combined with sonographic examinations for the fetus is effective in detecting foetus with trisomy 18.