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Table 5 Umbilical artery resistance index (female)

From: Sex differences in umbilical artery Doppler indices: a longitudinal study

Gestation (week) 2.5th percentile 5th percentile 10th percentile 25th percentile Mean 75th percentile 90th percentile 95th percentile 97.5th percentile
20 0.63 0.65 0.68 0.72 0.76 0.80 0.84 0.86 0.88
21 0.62 0.64 0.67 0.71 0.75 0.79 0.83 0.85 0.87
22 0.61 0.63 0.66 0.70 0.74 0.78 0.82 0.84 0.86
23 0.60 0.62 0.65 0.69 0.73 0.77 0.81 0.83 0.85
24 0.59 0.61 0.64 0.68 0.72 0.76 0.80 0.82 0.84
25 0.58 0.60 0.62 0.67 0.71 0.75 0.79 0.81 0.83
26 0.57 0.59 0.61 0.65 0.70 0.74 0.78 0.80 0.82
27 0.56 0.58 0.60 0.64 0.69 0.73 0.77 0.79 0.81
28 0.54 0.57 0.59 0.63 0.68 0.72 0.76 0.78 0.80
29 0.53 0.56 0.58 0.62 0.67 0.71 0.75 0.77 0.79
30 0.52 0.54 0.57 0.61 0.66 0.70 0.74 0.76 0.78
31 0.51 0.53 0.56 0.60 0.65 0.69 0.73 0.75 0.77
32 0.50 0.52 0.55 0.59 0.64 0.68 0.72 0.74 0.76
33 0.48 0.51 0.53 0.58 0.63 0.67 0.71 0.74 0.76
34 0.47 0.49 0.52 0.57 0.61 0.66 0.70 0.73 0.75
35 0.46 0.48 0.51 0.55 0.60 0.65 0.69 0.72 0.74
36 0.44 0.47 0.50 0.54 0.59 0.64 0.68 0.71 0.73
37 0.43 0.45 0.48 0.53 0.58 0.63 0.67 0.70 0.72
38 0.41 0.44 0.47 0.52 0.57 0.62 0.66 0.69 0.71
39 0.40 0.43 0.46 0.51 0.56 0.61 0.65 0.68 0.70
40 0.38 0.41 0.44 0.49 0.55 0.60 0.65 0.67 0.69
  1. Sex-specific reference values of the umbilical artery resistance index (UA RI) for the 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97.5th percentiles during the second half of pregnancy (female fetuses)