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. Author manuscript; available in PMC: 2021 Jun 1.
Published in final edited form as: Prenat Diagn. 2020 Apr 20;40(7):831–837. doi: 10.1002/pd.5693

Table 1.

Baseline characteristics of patients included in statistical analysis (n = 2,366). Two triploid events were included in the trisomy category, with one triploid event the NIPS pass and one in the NIPS fail sub cohorts. Percentage of trisomy was calculated from a total of 71 as unknowns were excluded.

NIPS results
Total Fail Pass
(n = 2,366) (n = 103) (n = 2,263)
Fetal fraction
 Mean 9.4 2.8 9.7
 SD 4.3 0.8 4.2
 Median 8.8 2.9 9.0
 Q1 – Q3 6.6 – 11.6 2.3 – 3.3 6.9 – 11.8
BMI
 Mean 27.4 34.3 27.1
 SD 6.6 7.6 6.3
 Median 25.9 34.3 25.7
 Q1 – Q3 22.5 – 31 30.1 – 39.4 22.3 – 30.5
Gestational age (weeks)
 Mean 13.7 13.1 13.7
 SD 4.34 3.11 4.4
 Median 12.1 12.9 12.1
 Q1 – Q3 11.0 – 14.4 11.8 – 14.1 11 – 14.4
Presence of trisomy
 Yes (%) 33 2 (2.8) 31 (1.4)
 No (%) 2,296 69 (97.2) 2,227 (98.6)
 Unknown (%) 37 32 5
Fetal sex
 Male (%) 1,207 53 (51.5) 1,154 (51.7)
 Female (%) 1,129 50 (48.5) 1,079 (48.3)
 Unknown (%) 30 0 30
Maternal age (years)
 Mean 32.3 32.9 32.3
 SD 5.2 5.2 5.2
 Median 33 34 33
 Q1 – Q3 29 – 36 30 – 37 29 – 36