Table 1: Baseline maternal, labor and delivery characteristics of the study population Table 1: Baseline maternal, labor and delivery characteristics of the study population Table 1: Baseline maternal, labor and delivery characteristics of the study population Table 1: Baseline maternal, labor and delivery characteristics of the study population
Low volume (n=70,849) High volume (n=70,006) p value
Maternal age 28.8±5.6 28.6±5.6 <0.01
Gravidity 4±2.8 3.9±2.8 <0.01
Parity 3.5±2.4 3.5±2.4 <0.01
Previous miscarriages 20409 (28.8%) 19847 (28.4%) 0.06
Previous miscarriages>3 2453 (3.5%) 2476 (3.5%) 0.45
Previous cesarean delivery any 5320 (7.5%) 5051 (7.2%) 0.03
Assisted reproductive techniques 1444 (2%) 1512 (2.2%) 0.11
Hypertensive disorders of pregnancy 1269 (1.8%) 1306 (1.9%) 0.30
Diabetes (pre-gestational + gestational) 2709 (3.8%) 2517 (3.6%) 0.02
Gestational age at delivery weeks 39.5±1.2 39.5±1.2 0.01
Meconium-stained amniotic fluid 11571 (16.3%) 11300 (16.1%) 0.33
Epidural analgesia 39038 (55.1%) 38433 (54.9%) 0.45
Chorioamnionitis 138 (0.2%) 164 (0.2%) 0.11
Persistent occiput posterior 2227 (3.1%) 2363 (3.4%) 0.01
Induction of labor 6151 (8.7%) 6059 (8.7%) 0.86
Oxytocin augmentation of labor 13719 (19.4%) 13867 (19.8%) 0.04
Birthweight grams 3336.5±423.7 3338.5±423 0.37
Birthweight>4000 grams 4440 (6.3%) 4393 (6.3%) 0.95
Large for gestational age 10259 (14.5%) 10102 (14.4%) 0.79
Small for gestational age 4268 (6%) 4289 (6.1%) 0.42
Second stage duration, hours 0:32:40±1:12:28 0:33:30±1:18:13 0.04
Prolonged second stage 2592 (3.7%) 2573 (3.7%) 0.87
Data are mean± standard deviation; number (%); Data are mean± standard deviation; number (%); Data are mean± standard deviation; number (%); Data are mean± standard deviation; number (%);