Statistical analysis
Results and graphics were completed using R software (version 3.6.3).
Previous studies have indicated that the yield of pCNV is unrelated to
maternal age.31 Therefore, 12730 fetuses with maternal
age ≥ 35 years and normal ultrasonography, defined as “fetuses with no
identifiable anomalies”, were used as a control cohort for comparison
of the yield of pCNV for fetuses with abnormal ultrasonographic
findings. The association between ultrasonographic findings and pCNV
were performed by Binomial test and Fisher’s exact test with Bonferroni
correction. P < 0.05 was considered statistically significant.