Table 1 Comparison of maternal, perinatal, and neonatal characteristics between two groups according to the presence of neonatal seizures.

Maternal age

33 [31, 36]

34 [30, 36]

33 [31, 36]

33 [30, 36]

33 [31, 36]

34 [31, 36]

Maternal education ≥ college

8,545 (57.5%)

785 (54.9%)

5,673 (76.6%)

162 (76.1%)

22 (64.7%)

4 (80.0%)

Multiple gestation^**

5,492 (37.0%)

517 (36.2%)

1,633 (32.3%)

400 (36.3%)

3,844 (39.4%)

114 (35.3%)

Cesarean section^*

11,879 (80.0%)

1,052 (73.6%)

3,679 (72.7%)

781 (70.9%)

8,169 (83.8%)

267 (82.7%)

In-vitro fertilization

3,812 (25.7%)

377 (26.4%)

1,301 (25.7%)

306 (27.8%)

2,504 (25.7%)

70 (21.7%)

Gestational diabetes^*

1,320 (8.9%)

91 (6.4%)

350 (6.9%)

59 (5.4%)

966 (9.9%)

31 (9.6%)

PIH^*,**

3,044 (20.5%)

155 (10.8%)

502 (9.9%)

86 (7.8%)

2,533 (26.0%)

69 (21.4%)

HCA^*,**

4,105 (32.6%)

564 (46.5%)

2,058 (47.7%)

490 (51.8%)

2,040 (24.8%)

73 (27.7%)

Oligohydramnios^†

2,029 (14.8%)

202 (15.8%)

753 (16.3%)

146 (14.9%)

1,263 (14.0%)

55 (18.8%)

GA, weeks^*,**,†

29^+ 1 [27^+ 0, 31^+ 0]

25^+ 5 [24^+ 2, 27^+ 5]

26^+ 1 [25^+ 0, 27^+ 1]

25^+ 0 [24^+ 0, 26^+ 1]

30^+ 2 [29^+ 1, 32^+ 0]

29^+ 4 [28^+ 3, 30^+ 6]

Birthweight, g^*,**,†

1,150 [890, 1340]

790 [635.5, 1010]

840 [685, 985]

730 [600, 880]

1280 [1120, 1400]

1200 [1000, 1350]

Male gender^*,**

7,356 (49.5%)

803 (56.2%)

2,640 (52.2%)

630 (57.2%)

4,704 (48.3%)

171 (52.9%)

Congenital anomaly^*,†

514 (3.5%)

75 (5.2%)

131 (2.6%)

38 (3.4%)

374 (3.8%)

35 (10.8%)

Inborn^*,**,†

14,423 (97.1%)

1,345 (94.1%)

4,899 (96.8%)

1,050 (95.3%)

9,483 (97.3%)

291 (90.1%)

Any antenatal steroid use^*,**,†

12,135 (82.9%)

1,073 (77.1%)

4,230 (84.8%)

847 (78.7%)

7,898 (82.2%)

226 (72.7%)

AS 5 min^*,**,†

7 [6, 8]

6 [4, 7]

6 [5, 7]

6 [4, 7]

8 [7, 8]

7 [5, 7]

Cord pH^*,**

7.27 [7.21, 7.33]

7.25 [7.15, 7.31]

7.27 [7.19, 7.34]

7.25 [7.17, 7.32]

7.28 [7.21, 7.33]

7.25 [7.12, 7.31]

DR resuscitation^*,**,†

13,105 (88.8%)

1,399 (98.7%)

4,954 (98.5%)

1,088 (99.5%)

8,120 (83.8%)

307 (96.2%)

Small for GA^*,**

3,483 (23.5%)

222 (15.5%)

437 (8.6%)

126 (11.4%)

3,003 (30.8%)

91 (28.2%)

Surfactant use^*,**,†

11,133 (75.0%)

1,378 (96.4%)

4,931 (97.4%)

1,095 (99.4%)

6,199 (63.6%)

281 (97.0%)

PDA with treatment^*,†

4,952 (34.5%)

674 (49.9%)

2,571 (53.0%)

552 (52.2%)

2,376 (25.1%)

121 (38.5%)

Hypotension within one-week-old^*,**,†

3,347 (22.5%)

1,001 (70.0%)

2,171 (42.9%)

814 (73.9%)

1,174 (12.0%)

184 (57.0%)

IVH ≥ grade 3^*,**,†

685 (4.8%)

732 (53.6%)

494 (10.6%)

623 (59.6%)

191 (2.0%)

109 (34.5%)

Post-hemorrhagic hydrocephalus^*,**,†

246 (1.7%)

368 (28.5%)

173 (3.8%)

302 (31.1%)

73 (0.8%)

66 (21.0%)

Sepsis within 14 days after birth^*,**,†

1,177 (8.0%)

271 (19.0%)

698 (13.9%)

222 (20.2%)

476 (4.9%)

49 (15.2%)

Meningitis^*,**,†

40 (0.3%)

46 (3.2%)

20 (0.4%)

38 (3.4%)

288 (3.0%)

41 (12.7%)

NEC ≥ stage 2^*,**,†

817 (5.5%)

262 (18.6%)

529 (10.6%)

221 (20.5%)

288 (3.0%)

41 (12.7%)