Maternal age (yr) |
33 (30–36) |
33 (30–36) |
34 (32–36) |
0.078* |
Primiparity (%) |
46.7 (652/1,396) |
46.7 (652/1,396) |
42.2 (27/64) |
0.479** |
Body mass index (kg/m2) before pregnancy |
21.0
(19.4–23.4) |
21.0 (19.4–23.4) |
21.5 (19.1–25.9) |
0.425* |
History of preterm delivery (%) |
10.0 (140/1,396) |
10.0 (140/1,396) |
18.8 (12/64) |
0.026** |
Multifetal pregnancy |
|
|
|
|
Twin (%) |
18.5 (258/1,396) |
18.5 (258/1,396) |
21.9 (14/64) |
0.495** |
Triplet (%) |
1.7 (24/1,396) |
3.1 (2/64) |
3.1 (2/64) |
0.406*** |
Pregnancy by in vitro fertilization-embryo transfer (%) |
17.6
(245/1,396) |
29.7 (19/64) |
29.7 (19/64) |
0.014** |
Pregnancy by intrauterine insemination (%) |
2.2 (31/1,396) |
3.1
(2/64) |
3.1 (2/64) |
0.634*** |
Gestational age at admission (wk) |
29.00 (24.6–32.9) |
24.3
(20.9–26.9) |
24.3 (20.9–26.9) |
<0.001* |
Diagnosis at admission |
|
|
|
|
Preterm premature rupture of membrane (%)
|
39.8 (556/1,396)
|
39.1 (25/64)
|
39.1 (25/64)
|
0.903**
|
Incompetent internal os of the cervix (%)
|
16.8 (235/1,396)
|
35.94 (23/64)
|
35.94 (23/64)
|
<0.001**
|
Cerclage (%) |
9.2 (129/1,396) |
29.7 (19/64) |
29.7 (19/64) |
<0.001** |
Preterm labor (%) |
38.9 (543/1,396) |
28.1 (18/64) |
28.1 (18/64) |
0.083** |
Short cervical length (%) |
5.6 (78/1,396) |
6.3 (4/64) |
6.3 (4/64) |
0.822*** |
Prior antibiotic treatment (%) |
15.0 (210/1,396) |
43.8 (28/64) |
43.8
(28/64) |
<0.001** |
Duration of prior antibiotic treatment (d) |
4.0 (2.0–8.0) |
7.0
(5.0–12.0) |
7.0 (5.0–12.0) |
0.015* |