Error Factor for Menstrual Age Dating: The 8% Factor
Example: 19wks 4days: 19x7 = 133+4 = 137 --> 137x0.08 = +/-10.96 days
1 wk +/- 0.56 days
3 wks +/- 1.68 days
4 wks +/- 2.24 days
5 wks +/- 2.80 days
6 wks +/- 3.36 days
7 wks +/- 4.41 days
8 wks +/- 4.48 days
9 wks +/- 5.04 days
10 wks +/- 5.60 days
11 wks +/- 6.16 days
12 wks +/- 6.70 days
13 wks +/- 7.28 days
14 wks +/- 7.48 days
15 wks +/- 8.40 days
16 wks +/- 8.96 days
17 wks +/- 9.52 days
18 wks +/- 10.08 days
19 wks +/- 10.64 days
20 wks +/- 11.20 days
21 wks +/- 11.76 days
22 wks +/- 12.32 days
23 wks +/- 12.88 days
24 wks +/- 13.44 days
25 wks +/- 14.00 days
26 wks +/- 14.56 days
27 wks +/- 15.12 days
28 wks +/- 15.60 days
29 wks +/- 16.24 days
30 wks +/- 16.80 days
31 wks +/- 17.36 days
32 wks +/- 17.92 days
33 wks +/- 18.48 days
34 wks +/- 19.04 days
35 wks +/- 19.60 days
36 wks +/- 20.16 days
37 wks +/- 20.72 days
38 wks +/- 21.28 days
39 wks +/- 21.84 days
40 wks +/- 22.40 days