Maternal and Fetal Risk Factors for Neonatal Hypoxic-Ischemic Encephalopathy: A Retrospective Study

Figures & data

Table 1 Comparison of Clinical Characteristics between the Two Groups

Variables	Total (n=258)	Control Group (n=148)	Neonatal Hypoxic-Ischemic Encephalopathy Group (n=110)	P value
Gender
Male	175 (67.8%)	99 (66.9%)	76 (69.1%)	0.788
Female	83 (32.2%)	49 (33.1%)	34 (30.9%)
Mode of delivery
Spontaneous	149 (57.8%)	84 (56.8%)	65 (59.1%)	0.799
Cesarean section	109 (42.2%)	64 (43.2%)	45 (40.9%)
Gestational age (weeks)
<37	68 (26.4%)	50 (33.8%)	18 (16.4%)	0.003
37–42	190 (73.6%)	98 (66.2%)	92 (83.6%)
Birth weight (kg)
<2.5	63 (24.4%)	49 (33.1%)	14 (12.7%)	<0.001
2.5–4.0	186 (72.1%)	96 (64.9%)	90 (81.8%)
>4.0	9 (3.5%)	3 (2.0%)	6 (5.5%)
Adverse pregnancy history
No	197 (76.4%)	108 (73.0%)	89 (80.9%)	0.142
Yes	61 (23.6%)	40 (27.0%)	21 (19.1%)
Perinatal conditions
Amniotic fluid contamination
No	177 (68.6%)	119 (80.4%)	58 (52.7%)	<0.001
Yes	81 (31.4%)	29 (19.6%)	52 (47.3%)
Nuchal cord
No	185 (71.7%)	102 (68.9%)	83 (75.5%)	0.002
Yes	62 (24.0%)	44 (29.7%)	18 (16.4%)
Unknown	11 (4.3%)	2 (1.4%)	9 (8.2%)
Placenta abnormality
No	224 (86.8%)	134 (90.5%)	90 (81.8%)	0.104
Yes	9 (3.5%)	3 (2.0%)	6 (5.5%)
Unknown	25 (9.7%)	11 (7.4%)	14 (12.7%)
1-minute Apgar score	6.16±3.54	8.72±1.80	2.72±2.06	<0.001
5-minute Apgar score	7.91±2.57	9.53±1.05	5.72±2.38	<0.001

Table 2 Logistic Regression Analysis of Risk of Neonatal Hypoxic-Ischemic Encephalopathy

Variables	Adjusted Odds Ratio (OR)	95% Confidence Interval (CI) for Adjusted Odds Ratio	P value
Gender
Male	1.000 (Reference)
Female	1.134	0.368–3.495	0.827
Mode of delivery
Spontaneous	1.000 (Reference)
Cesarean section	0.653	0.196–2.175	0.487
Gestational age (weeks)
37–42	1.000 (Reference)
<37	1.600	0.284–9.025	0.594
Birth weight (kg)
<2.5	1.780	0.124–25.463	0.016
2.5–4.0	1.000 (Reference)
>4.0	0.084	0.011–0.625	0.671
Adverse pregnancy history
No	1.000 (Reference)
Yes	0.392	0.102–1.509	0.173
Perinatal conditions
Amniotic fluid contamination
No	1.000 (Reference)
Yes	3.223	1.049–9.901	0.041
Nuchal cord
No	1.000 (Reference)
Yes	0.379	0.106–1.359	0.136
Placenta abnormality
No	1.000 (Reference)
Yes	1.224	0.016–92.757	0.927
1-minute Apgar score
>3	1.000 (Reference)
≤3	92.425	15.522–550.343	<0.001
5-minute Apgar score
>7	1.000 (Reference)
≤7	12.641	2.894–55.227	0.001

Figure 1 ROC curves of 1-minute Apgar score and 5-minute Apgar score for HIE.

Table 3 Independent Risk Factors of Hypoxic-Ischemic Encephalopathy in Neonates Born to Women with or without Previous Childbearing History

Variables	Newborns Born to Women without Previous Childbearing History		Newborns Born to Women with Previous Childbearing History
	Adjusted OR (95% CI)	P value	Adjusted OR (95% CI)	P value
Gender
Male	1.000 (Reference)		1.000 (Reference)
Female	0.966 (0.224–4.162)	0.963	1.507 (0.109–20.741)	0.759
Mode of delivery
Spontaneous	1.000 (Reference)		1.000 (Reference)
Cesarean section	0.722 (0.140–3.715)	0.697	0.541 (0.048–6.116)	0.619
Gestational age (weeks)
37–42	1.000 (Reference)		1.000 (Reference)
<37	1.391 (0.108–17.971)	0.800	/	0.994
Birth weight (kg)
<2.5	1.068 (0.009–3.216)	0.236	/	0.994
2.5–4.0	1.000 (Reference)		1.000 (Reference)
>4.0	/	0.999	7.085 (0.182–275.369)	0.294
Adverse pregnancy history
Yes	/	/	1.000 (Reference)
No	/	/	0.650 (0.090–4.682)	0.669
Perinatal conditions
Amniotic fluid contamination
No	1.000 (Reference)		1.000 (Reference)
Yes	5.695 (1.345–24.120)	0.018	1.044 (0.112–9.728)	0.970
Nuchal cord
No	1.000 (Reference)		1.000 (Reference)
Yes	0.180 (0.030–1.091)	0.062	1.194 (0.086–16.650)	0.895
Placenta abnormality
No	1.000 (Reference)		1.000 (Reference)
Yes	/	0.999	/	0.998
1-minute Apgar score
>3	1.000 (Reference)		1.000 (Reference)
≤3	32.518 (3.326–317.891)	0.003	/	0.992
5-minute Apgar score
>7	1.000 (Reference)		1.000 (Reference)
≤7	15.411 (2.570–92.417)	0.003	/	0.995