Table 5 Association of maternal CRP, C3, C4 and ferritin levels and the risk of PTB in the third trimester

CRP

0.964

 P50 < 17.77

12

22

1.00

–

1.00

–

 P50 - P75 (17.77–24.08)

4

11

0.68 (0.20–2.34)

0.537

0.77 (0.21–2.85)

0.700

 P75 > 24.08

6

10

1.19 (0.35–4.00)

0.779

1.22 (0.36–4.18)

0.748

C3

0.228

 P50 < 1443.00

14

22

1.00

–

1.00

 P50 - P75 (1443.00–1640.00)

6

11

0.69 (0.19–2.57)

0.583

0.64 (0.17–2.38)

0.507

 P75 > 1640.00

2

10

0.17 (0.02–1.77)

0.140

0.16 (0.02–1.65)

0.124

C4

0.433

 P50 < 255.00

8

22

1.00

–

1.00

–

 P50 - P75 (255.00–349.00)

9

11

3.11 (0.76–12.7)

0.115

2.80 (0.66–11.78)

0.162

 P75 > 349.00

5

10

1.68 (0.44–6.41)

0.449

1.61 (0.41–6.26)

0.493

ferritin

0.702

 P50 < 10.34

9

22

1.00

–

1.00

–

 P50 - P75 (10.34–18.81)

9

11

1.91 (0.62–5.86)

0.258

1.66 (0.54–5.15)

0.378

 P75 > 18.81

4

10

0.94 (0.24–3.78)

0.935

0.58 (0.12–2.82)

0.500