Table 3 Duration of second stage of labor and rates, and risks of umbilical artery acidosis, birth asphyxia-related complications and admission to NICU

From: Durations of second stage of labor and pushing, and adverse neonatal outcomes: a population-based cohort study

  Acidosisa (N=360) Birth asphyxia-related complicationsb (N=269) Admission to NICU (N=2733)
  N totalc % aRR d (95% CI) N total % aRR d (95% CI) % aRR d (95% CI)
  33 429 1.08    42 539 0.63    6.42   
Second stage (h)            
 <1 10 518 0.99 1.00 Reference 13 558 0.42 1.00 Reference 4.97 1.00 Reference
 1 to <2 9690 1.12 1.10 (0.84–1.45) 12 225 0.53 1.19 (0.83–1.70) 6.02 1.22 (1.10–1.35)
 2 to <3 6130 1.27 1.19 (0.88–1.60) 7710 0.77 1.59 (1.10–2.31) 7.11 1.41 (1.26–1.57)
 3 to <4 4115 0.92 0.77 (0.52–1.14) 5238 0.74 1.56 (1.04–2.35) 7.92 1.57 (1.39–1.77)
4 2976 1.04 0.84 (0.55–1.28) 3808 1.29 2.46 (1.66–3.66) 9.45 1.80 (1.58–2.04)
  1. Abbreviations: aRR, adjusted relative risk; CI, confidence interval; HIE, hypoxic ischemic encephalopathy; MAS, meconium aspiration syndrome; NICU, neonatal intensive care unit.
  2. aAcidosis: umbilical artery acidosis, pH <7.05 and BE <−12.
  3. bBirth asphyxia-related complications include any of the following conditions: HIE, hypothermia treatment, neonatal seizures, MAS or advanced resuscitation after birth (heart compressions or intubation).
  4. cMissing data on pH and/or BE: N=9110.
  5. dAdjusted for: maternal characteristics: maternal age, height, BMI, smoking, hypertensive disease and diabetes. Delivery and fetal characteristics: onset of delivery (spontaneous or induction), oxytocin before retracted cervix and gestational length at birth.