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Table 2 Clinical and labor characteristics evaluated as risk factors for hypoxic ischemic encephalopathy

From: Intrapartum factors associated with neonatal hypoxic ischemic encephalopathy: a case-controlled study

Characteristic Cases
(N = 26)
N (%)
Controls
(N = 104)
N (%)
Univariate analysis Multivariable analysisg
Unadjusted OR (95% CI) P Adjusted OR (95% CI) P
Prior cesarean delivery 6 (23.1%) 11 (10.6%) 2.53 (0.83, 7.75) 0.10   
Chronic hypertension 2 (7.7%) 1 (1.0%) 8.00 (0.72, 88.23) 0.09   
Gestational diabetes 1 (3.8%) 4 (3.8%) 1.00 (0.02, 10.11) 1.00   
Fetal growth restriction 0 (0%) 2 (1.9%) 1.66 (0, 13.89) 1.00   
Oligohydramnios 1 (3.8%) 2 (1.9%) 2.00 (0.18, 22.06) 0.57   
Preterm labor 2 (7.7%) 4 (3.8%) 2.67 (0.33, 21.54) 0.36   
Meconium-stained amniotic fluida 11 (42.3%) 16 (15.4%) 4.62 (1.63, 13.06) 0.004 12.41 (2.10, 144.83) 0.002
Chorioamnionitis 2 (7.7%) 3 (2.9%) 3.15 (0.43, 23.36) 0.26   
Oxytocin use 14 (53.8%) 50 (48.1%) 1.26 (0.53, 3.00) 0.60   
Abnormal first stage of laborb,c 12/17 (70.6%) 48/94 (51.1%) 2.19 (0.71, 6.76) 0.17   
Prolonged second stage of labord 5/17 (29.4%) 4/91 (4.4%) 11.24 (1.92, 65.58) 0.007 9.49 (1.06, 135.30) 0.042
Any sentinel or acute evente 6 (23.1%) 0 (0%) 32.66 (6.18, infinity) < 0.001 74.86 (11.86, infinity) < 0.001
Any ‘category 3’ segment in the last hour of laborf 7/25 (28.0%) 4/101 (4.0%) 7.30 (2.11, 25.30) 0.002   
  1. aMeconium-stained amniotic fluid present either before or after 6 cm of dilation
  2. bThe first stage of labor could not be classified for 9 HIE cases and 10 controls because they either have a cesarean section without laboring (N = 5 cases and N = 6 controls) or they first presented at 10 cm (N = 2 controls) or they never reached an active phase before proceeding to a cesarean section (N = 1 case and N = 1 control) or they only had 1 measurement in the active phase before proceeding to a cesarean section (N = 3 case and N = 1 control)
  3. cAbnormal first stage of labor included patients with protracted labor (cervical dilation <1.2 cm per hour), secondary arrest (lack of cervical dilation for >2 h after patient reached 7 cm) and combined disorders (patients with both protracted labor and secondary arrest)
  4. dThe second stage of labor could not be classified for 9 HIE cases and 13 controls because they either have a cesarean section without laboring (N = 5 cases and N = 6 controls) or they did not reach 10 cm before proceeding to a cesarean section (N = 4 cases and N = 7 controls)
  5. eA sentinel event was defined as an acute event that emergently altered the course of labor; these included uterine rupture, cord prolapse, placental abruption, fetal exsanguination/vasa previa, amniotic fluid embolism, and maternal collapse
  6. fOne HIE case and 3 controls had insufficient information for categorizing the fetal heart tracings
  7. gMultivariable exact conditional logistic regression models were fit considering all variables with p < 0.20 based on univariate analysis and first examining all one-variable models, all two-variable models, and all three-variable models. Variables were retained in the final multivariable model if p < 0.05