Table 1. . Detection rates of abnormal karyotype in different indications of prenatal diagnosis.
| Indications of prenatal diagnosis | Cases (%) | Abnormal karyotype (n) | Positive detection rate (%) |
|---|---|---|---|
| Pathological ultrasound finding | 383 (12.287%) | 52 | 13.577 |
| Advanced maternal age | 842 (27.013%) | 83 | 9.857 |
| Prenatal serum screening tests | 1007 (32.307%) | 62 | 6.157 |
| Noninvasive prenatal DNA testing | 760 (24.382%) | 325 | 42.763 |
| At least one of the couple has abnormal karyotype | 115 (3.689%) | 26 | 22.609 |
| Pregnant women with a history of adverse pregnancy and childbirth | 254 (8.149%) | 4 | 1.575 |
| Test-tube baby | 5 (0.160%) | 1 | 20.000 |
| Pregnant women requested an amniocentesis | 26 (0.834%) | 0 | 0.000 |
| Total | 3117 (100%) | 434 | 13.924 |
Pregnant women with two or more amniocentesis indications were included in different groups for repeated statistics.