Total (n = 1,460)
Negative for ESBL-E (n = 1,396) Negative for ESBL-E (n = 1,396)
Positive for ESBL-E (n = 64)
P-value
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*