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. 2016 Nov 13;96(1):86–95. doi: 10.1111/aogs.13034

Table 1.

Correlates of large discrepancies between pregnancy dating methods. Odds ratios (OR) with 95% confidence intervals (95% CI) for large negative discrepancy (below the 10th percentile in the discrepancy distribution; −9 to −20 days) and large positive discrepancy (above the 90th percentile in the discrepancy distribution; +4 to +20 days) between EDD‐LMP and EDD‐USa in association with maternal characteristics at the first antenatal visit, fetal sex, and maternal medical history variables

Large negative discrepancies Large positive discrepancies
n Neg (%)b Ref (%)c cOR 95% CI aORe 95% CI n Pos (%)d Ref (%)c cOR 95% CI aORe 95% CI
Age at delivery (years)
<20 18 662 5 3 1.84 1.78–1.90 1.79 1.71–1.86 15 712 3 3 1.14 1.09–1.19 1.05 1.00–1.11
20–24 109 111 24 16 1.42 1.40–1.44 1.40 1.37–1.43 96 840 14 16 1.00 0.98–1.03 1.00 0.97–1.02
25–29 226 304 38 35 1.00 – 1.00 – 217 512 32 35 1.00 – 1.00 –
30–34 198 848 25 33 0.71 0.69–0.72 0.68 0.67–0.70 206 725 33 33 1.11 1.09–1.13 1.12 1.10–1.14
35–39 73 707 7 13 0.54 0.53–0.56 0.49 0.48–0.50 81 893 15 13 1.30 1.28–1.33 1.29 1.26–1.32
>40 10 300 1 2 0.46 0.43–0.49 0.38 0.35–0.40 12 211 3 2 1.60 1.53–1.67 1.57 1.50–1.65
Total 636 932 100 100 630 893 100 100
Height (cm)
<160 119 842 22 18 1.22 1.21–1.24 1.17 1.15–1.20 113 261 17 18 0.98 0.96–1.00 0.96 0.94–0.98
160–172f 412 279 64 65 1.00 – 1.00 – 407 312 63 65 1.00 – 1.00 –
>172 104 811 14 17 0.82 0.81–0.84 0.86 0.84–0.88 110 320 20 17 1.17 1.15–1.19 1.19 1.17–1.21
Total 636 932 100 100 630 893 100 100
BMI classes according to WHO classification
Underweight 15 836 3 2 1.36 1.31–1.42 1.18 1.13–1.24 15 049 3 2 1.03 0.98–1.07 1.03 0.98–1.09
Normal range 402 285 60 64 1.00 – 1.00 – 404 877 65 64 1.00 – 1.00 –
Pre‐obese 153 378 24 24 1.08 1.06–1.09 1.07 1.05–1.08 151 804 24 24 0.98 0.97–1.00 0.97 0.95–0.98
Obese class I 47 165 9 7 1.39 1.36–1.42 1.34 1.30–1.37 43 689 7 7 0.91 0.89–0.94 0.90 0.87–0.92
Obese class II 13 860 3 2 1.74 1.68–1.81 1.70 1.63–1.78 11 950 2 2 0.83 0.79–0.87 0.80 0.76–0.85
Obese class III 4408 1 1 2.18 2.05–2.33 2.16 2.01–2.33 3524 1 1 0.78 0.71–0.86 0.74 0.66–0.82
Total 636 932 100 100 630 893 100 100
Living with partner
Yes 599 095 93 94 1.00 – 1.00 – 593 478 93 94 1.00 – 1.00 –
No 30 259 6 5 1.23 1.20–1.27 0.99 0.95–1.02 30 030 6 5 1.25 1.22–1.29 1.21 1.17–1.25
Missing 7578 1 1 7385 1 1
Total 636 932 100 100 630 893 100 100
Employed
Yes 461 462 68 74 1.00 – 1.00 – 461 500 71 74 1.00 – 1.00 –
No 113 304 21 17 1.32 1.30–1.34 1.09 1.07–1.11 109 636 19 17 1.12 1.10–1.14 1.16 1.14–1.19
Missing 62 166 12 9 59 757 10 9
Total 636 932 100 100 630 893 100 100
Smoking at first antenatal visit
No 568 365 87 90 1.00 – 1.00 – 565 880 89 90 1.00 – 1.00 –
Yes 59 502 12 9 1.35 1.33–1.38 1.13 1.11–1.16 56 077 9 9 1.04 1.02–1.07 1.04 1.02–1.07
Missing 9065 2 1 8936 1 1
Total 636 932 100 100 630 893 100 100
Snuff use at first antenatal visitg
No 483 073 73 77 1.00 – 1.00 – 481 672 75 77 1.00 – 1.00 –
Yes 5844 1 1 1.16 1.09–1.24 1.12 1.05–1.20 5670 1 1 1.01 0.94–1.08 1.01 0.94–1.09
Missing 148 015 26 23 143 551 24 23
Total 636 932 100 100 630 893 100 100
Parity
0‐parous 280 971 45 44 1.00 – 1.00 – 276 029 43 44 1.00 – 1.00 –
1‐parous 236 861 36 38 0.92 0.91–0.93 1.05 1.03–1.07 233 995 35 38 0.94 0.93–0.96 0.91 0.89–0.92
2‐parous 85 121 13 13 0.94 0.92–0.95 1.20 1.17–1.24 86 219 15 13 1.10 1.08–1.12 1.02 0.99–1.04
3‐parous 22 807 4 4 1.04 1.00–1.07 1.40 1.34–1.46 23 246 4 4 1.25 1.21–1.29 1.13 1.08–1.17
4‐parous or more 11 172 2 2 1.24 1.19–1.30 1.77 1.67–1.87 11 404 3 2 1.49 1.43–1.56 1.29 1.23–1.37
Total 636 932 100 100 630 893 100 100
Fetal sex
Male 319 057 44 52 1.00 – 1.00 – 340 140 65 52 1.76 1.74–1.78 1.80 1.77–1.83
Female 317 875 56 49 1.34 1.33–1.36 1.36 1.34–1.38 290 753 35 49 1.00 – 1.00 –
Total 636 932 100 100 630 893 100 100
Medical history variablesh
Diabetes mellitus
No 635 613 100 100 1.00 – 1.00 – 629 860 100 100 1.00 – 1.00 –
Yes 1319 0 0 2.15 1.91–2.41 1.95 1.69–2.25 1033 0 0 0.78 0.65–0.92 0.86 0.70–1.04
Total 636 932 100 100 630 893 100 100
Gestational diabetes in a former pregnancyi
No 353 236 99 99 1.00 – 1.00 – 353 236 99 100 1.00 – 1.00 –
Yes 2725 1 1 1.61 1.48–1.75 1.47 1.38–1.63 2725 1 0 0.75 0.67–0.85 0.74 0.65–0.84
Total 355 961 100 100 355 961 100 100
Hypertensive disorders
No 636 565 100 100 1.00 – 1.00 – 630 560 100 100 1.00 – 1.00 –
Yes 367 0 0 1.37 1.08–1.74 1.26 0.94–1.68 333 0 0 0.88 0.66–1.18 0.76 0.54–1.07
Total 636 932 100 100 630 893 100 100
Preeclampsia in a former pregnancyi
No 345 235 96 97 1.00 – 1.00 – 345 235 98 97 1.00 – 1.00 –
Yes 10 726 4 3 1.22 1.17–1.28 1.16 1.09–1.23 10 726 2 3 0.86 0.82–0.91 0.92 0.86–0.98
Total 355 961 100 100 355 961 100 100
Hypothyroidism
No 635 635 100 100 1.00 – 1.00 – 629 595 100 100 1.00 – 1.00 –
Yes 1297 0 0 0.91 0.78–1.05 0.97 0.82–1.14 1298 0 0 0.96 0.83–1.11 0.85 0.72–1.01
Total 636 932 100 100 630 893 100 100
Systematic lupus erythematosus
No 636 720 100 100 1.00 – 1.00 – 630 695 100 100 1.00 – 1.00 –
Yes 212 0 0 1.17 0.84–1.63 1.24 0.83–1.84 198 0 0 0.85 0.58–1.25 0.79 0.50–1.24
Total 636 932 100 100 630 893 100 100
Ulcerative colitis
No 636 163 100 100 1.00 – 1.00 – 630 101 100 100 1.00 – 1.00 –
Yes 769 0 0 0.76 0.62–0.92 0.82 0.64–1.04 792 0 0 0.96 0.80–1.15 1.09 0.89–1.34
Total 636 932 100 100 630 893 100 100
Crohn's disease
No 636 174 100 100 1.00 – 1.00 – 630 124 100 100 1.00 – 1.00 –
Yes 758 0 0 0.92 0.77–1.11 0.92 0.73–1.14 769 0 0 1.05 0.88–1.26 1.17 0.96–1.44
Total 636 932 100 100 630 893 100 100
Depressive disorders
No 634 329 100 100 1.00 – 1.00 – 628 468 100 100 1.00 – 1.00 –
Yes 2603 1 0 1.26 1.15–1.38 1.09 0.98–1.21 2425 0 0 0.92 0.83–1.03 0.91 0.81–1.03
Total 636 932 100 100 630 893 100 100
Anxiety disorders and phobias
No 635 326 100 100 1.00 – 1.00 – 629 406 100 100 1.00 – 1.00 –
Yes 1606 0 0 1.30 1.16–1.47 1.14 1.00–1.30 1487 0 0 0.93 0.81–1.07 0.92 0.79–1.07
Total 636 932 100 100 630 893 100 100
a

Estimated due date based on the date of the last menstrual period (EDD‐LMP) and estimated due date based ultrasound biometry (EDD‐US).

b

Pregnancies with negative discrepancy below the 10th percentile (−9 to −20 days), n = 119 275 births.

c

Reference category is median discrepancy ±2 days (−1 to +3 days), n = 517 657 births.

d

Pregnancies with positive discrepancy above the 90th percentile (+4 to +20 days), n = 113 236 births.

e

Adjusted, as appropriate, for age, parity, height, BMI, smoking at first antenatal visit, and employment status.

f

Mean ± 1 SD.

g

Variable available for analyses for births in years 2000–2010.

h

Inpatient diagnoses registered at least once from 5 years to 9 months before registered birth.

i

Analyses excluding 0‐parous women.

[Correction added on 23 December 2016 after online publication: In Table 1, the values of Male and Female Fetal Sex under Large positive discrepancies have been corrected.]