Table 1 Frequencies and types of chromosomal abnormalities in second trimester amniocentesis, N = 21,120.

From: Frequency and clinical significance of chromosomal inversions prenatally diagnosed by second trimester amniocentesis

Type

Number

Frequency (%)

Normal variant inversions

303

1.43

46,XN,inv(9)(p12q13)

237

1.12

46,X,inv(Y)(p11.2q11.2)

65

0.31

46,X,inv(Y)(p11.2q11.2),inv(9)(p12q13)

1

 

Other inversions

56

0.27

Abnormal karyotype

Numerical abnormalities

459

2.17

Structural aberrations

468

2.22

Total

927

4.39

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