Table 3. Exploratory Analysis of Live-Born Infants at 22, 23, or 24 Weeks’ Gestational Age During 2004-2007 or 2014-2016 in Swedena.
| 22 Weeks’ Gestational Ageb | 23 Weeks’ Gestational Age | 24 Weeks’ Gestational Age | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. With Event/Total (%) | Difference, % (95% CI)d |
P Value | No. With Event/Total (%) | Difference, % (95% CI)d |
P Value | No. With Event/Total (%) | Difference, % (95% CI)d |
P Value | ||||
| 2004-2007c | 2014-2016 | 2004-2007c | 2014-2016 | 2004-2007c | 2014-2016 | |||||||
| Infant Characteristics | ||||||||||||
| Male sex | 25/49 (51) |
39/74 (53) |
−2 (−20 to 16) |
>.99 | 55/101 (55) |
82/148 (55) |
−1 (−14 to 12) |
.90 | 78/144 (54) |
119/192 (62) |
−8 (−18 to 2.8) |
.18 |
| Female sex | 24/49 (49) |
35/74 (47) |
2 (−16 to 20) |
>.99 | 46/101 (45) |
66/148 (45) |
1 (−12 to 14) |
.90 | 66/144 (46) |
73/192 (38) |
8 (−2.8 to 18) |
.18 |
| Singleton | 29/49 (59) |
54/74 (73) |
−14 (−31 to 3.3) |
.16 | 85/101 (84) |
115/148 (78) |
6 (−3.3 to 16) |
.26 | 112/144 (78) |
165/192 (86) |
−8 (−17 to 0.7) |
.06 |
| Twin or triplet | 20/49 (41) |
20/74 (27) |
14 (−3.3 to 31) |
.16 | 16/101 (16) |
33/148 (22) |
−6 (−16 to 3.3) |
.26 | 32/144 (22) |
27/192 (14) |
8 (−0.7 to 17) |
.06 |
| Apgar score <4e | ||||||||||||
| At 1 min after birth | 34/49 (69) |
49/73 (67) |
2 (−15 to 19) |
.94 | 53/101 (53) |
77/145 (53) |
−0.6 (−13 to 12) |
>.99 | 63/144 (44) |
76/188 (40) |
3 (−7.4 to 14) |
.58 |
| At 5 min after birth | 38/49 (71) |
35/71 (49) |
28 (12 to 44) |
.003 | 47/101 (47) |
42/146 (29) |
18 (5.6 to 30) |
.005 | 47/144 (33) |
44/188 (23) |
9 (−0.5 to 19) |
.06 |
| Small for gestational agef | 3/49 (6) |
4/73 (5.5) |
0.6 (−7.9 to 9.1) |
>.99 | 7/100 (7.0) |
14/146 (9.6) |
−3 (−0.5 to 4.3) |
.64 | 16/142 (11) |
31/187 (17) |
−5 (−13 to 2.1) |
.20 |
| Birth weight, median (range), g | 519 (290 to 730) |
489 (345 to 670) |
24 (−195 to 310) |
.12 | 590 (320 to 808) |
592 (300 to 1615) |
−1 (−295 to 270) |
.82 | 674 (374 to 1070) |
680 (380 to 930) |
−5 (−300 to 363) |
.46 |
| Obstetric Care Management | ||||||||||||
| Any antenatal steroids | 19/47 (40) |
47/73 (64) |
−24 (−42 to −6.1) |
.02 | 85/99 (86) |
132/144 (92) |
−6 (−14 to 2.4) |
.20 | 130/137 (95) |
169/187 (90) |
5 (−1.1 to 10) |
.15 |
| Cesarean delivery | 2/49 (4.1) |
4/74 (5.4) |
1 (−8.9 to 6.2) |
>.99 | 17/101 (17) |
50/148 (34) |
−17 (−28 to −6.4) |
.003 | 67/144 (46) |
110/191 (58) |
−11 (−22 to −0.3) |
.05 |
| Delivery at hospital with level III NICU | 22/49 (45) |
66/74 (89) |
−44 (−60 to −29) |
<.001 | 79/101 (78) |
127/148 (86) |
−8 (−17 to 2.2) |
.13 | 129/144 (90) |
162/192 (84) |
5 (−2.0 to 12) |
.20 |
| Delivery at hospital with level I-II NICU | 27/49 (55) |
8/74 (11) |
44 (29 to 60) |
<.001 | 22/101 (22) |
21/148 (14) |
8 (−2.7 to 18) |
.13 | 15/144 (10) |
30/192 (16) |
−5 (−12 to 2.0) |
.20 |
| Neonatal Care Management | ||||||||||||
| Neonatologist attending the birth | 22/48 (46) |
66/73 (90) |
−45 (−60 to −29) |
<.001 | 83/100 (83) |
132/147 (90) |
−7 (−16 to 2.0) |
.13 | 130/142 (92) |
168/192 (88) |
4 (−2.5 to 11) |
.29 |
| Intubation at birth | 12/21 (57) |
52/74 (70) |
−13 (−37 to 10) |
.38 | 68/84 (81) |
129/148 (87) |
−6 (−16 to 3.8) |
.25 | 113/142 (80) |
160/192 (83) |
−4 (−12 to 4.7) |
.39 |
| Surfactant administration <2 h after birth | 13/42 (31) |
50/74 (68) |
−37 (−54 to −19) |
<.001 | 72/95 (76) |
116/140 (83) |
−7 (−18 to 3.6) |
.19 | 120/140 (86) |
150/185 (81) |
5 (−3.5 to 13) |
.30 |
| Admission to NICUg | 18/48 (38) |
50/74 (68) |
−30 (−47 to −13) |
<.001 | 81/100 (81) |
138/148 (93) |
−12 (−21 to −3.6) |
.004 | 132/142 (93) |
191/192 (99) |
−7 (−11 to −2.2) |
.001 |
| Transportation of infant to level III NICU | 6/49 (12) |
6/74 (8.1) |
4 (−7.0 to 15) |
.65 | 13/101 (13) |
16/148 (11) |
2 (−6.2 to 10) |
.62 | 15/144 (10) |
24/192 (13) |
−2 (−8.9 to 4.8) |
.56 |
Abbreviation: NICU, neonatal intensive care unit.
a
Data for live-born infants at 25 or 26 weeks’ gestational age appear in Table 4.
b
Data for 22 infants identified in the Swedish medical birth registry but who were dead before admission were excluded from the data presented in the majority of rows.
c
Data are from Fellman et al.16
d
Difference in the prevalence for the 2004-2007 cohort minus the prevalence for the 2014-2016 cohort.
e
A score of 10 represents the best possible condition.
f
Some birth weights were missing because infants were not weighed until after birth.
g
Data for the 22 infants were included in this row (identified in the Swedish medical birth registry but who were dead before admission).