Analysis of Fetal Chromosomal Karyotypes in 247 Pregnant Women During the Second Trimester of Gestation

Objective To analyze the fetal chromosomal karyotypes in prenatal diagnosis and the relationship between abnormal karyotypes and the indications of prenatal diagnosis. Methods Fetal chromosomal karyotypes were examined in 247 pregnant women (16 to 28 weeks' gestation) by amniocentesis. Results 14 abnormal chromosomal karyotypes were detected, the abnormal rate was 5.67%. Trisomy was the major abnormality, it was 7out of 14(50%), including 4 trisomy 21(42.86%)?2 trisomy 18(28.57%)?1 trisomy 13(14.28%).Balanced translocation was found in 6 fetuses, the frequency was 42.86%. In 18 pregnant women aged over 35 years,1 (5.56%) with trisomy 21 was detected, and 3 of trisomy 21 were in 229 pregnant women aged under 35 years (1.31%,P=0.235). 3 Trisomy were detected in 15 fetuses with ultrasonographic suspected abnormalities. Conclusions During the second trimester, in the pregnant women who had different indications for prenatal diagnosis, the rate of chromosomal abnormality was 5.67%. Trisomy was the most common abnormal karyotype. As one method of prenatal screening, ultrasound in the second trimester could increase the antenatal detection rate of fetal chromosomal abnormality.