Table 3

Temporal Changes in Neonatal Mortality or Serious Neonatal Morbidity† by Plurality, Gestational Age and Subtype of Preterm Birth, United States, 1995-96 and 2004-05

1995-96

2004-05


Plurality and gestational age and preterm birth subtype

Live births

Neonatal outcomes†/100 live births

Live births

Neonatal outcomes†/100 live births

Odds ratio (2004-05 vs 1995-96)

95% confidence intervals


Singletons

24-27 wks: Iatrogenic

6,418

49.0

7,532

42.9

0.78*

0.73-0.83

Spontaneous

8,569

52.1

6,683

45.5

0.77*

0.72-0.82

PROM

4,728

51.0

3,338

49.9

0.95

0.87-1.04

28-31 wks: Iatrogenic

14,329

28.4

16,008

23.7

0.78*

0.74-0.82

Spontaneous

16,486

23.1

12,501

20.5

0.86*

0.82-0.91

PROM

8,083

26.9

5,402

26.3

0.97

0.89-1.04

32-33 wks: Iatrogenic

14,973

15.8

18,051

13.3

0.82*

0.77-0.87

Spontaneous

21,469

10.7

17,124

9.50

0.88*

0.82-0.94

PROM

9,955

12.3

6,662

12.9

1.06

0.97-1.16

34-36 wks: Iatrogenic

86,586

5.69

119,807

4.49

0.78*

0.75-0.81

Spontaneous

173,286

2.73

152,483

2.43

0.89*

0.85-0.93

PROM

35,844

4.83

22,801

5.64

1.18*

1.09-1.27

24-36 wks: Iatrogenic

122,306

11.9

161,398

9.17

0.75*

0.73-0.77

Spontaneous

219,810

6.95

188,791

5.80

0.82*

0.80-0.84

PROM

58,610

12.9

38,203

13.7

1.07*

1.03-1.12


Twins

24-27 wks: Iatrogenic

1,640

49.1

2,477

42.0

0.83*

0.73-0.94

Spontaneous

1,671

64.1

1,303

51.7

0.69*

0.60-0.80

PROM

933

59.3

844

55.2

0.85

0.70-1.02

28-31 wks: Iatrogenic

3,875

25.2

5,967

21.6

0.86*

0.78-0.94

Spontaneous

3,312

26.7

3,205

23.7

0.85*

0.76-0.95

PROM

1,889

30.9

1,679

28.5

0.89

0.77-1.03

32-33 wks: Iatrogenic

5,252

12.0

8,930

11.4

0.95

0.85-1.06

Spontaneous

4,981

10.8

4,540

10.9

1.02

0.90-1.16

PROM

1,986

14.7

1,839

13.7

0.92

0.77-1.10

34-36 wks: Iatrogenic

24,983

4.25

42,236

3.65

0.84*

0.78-0.91

Spontaneous

21,432

3.52

18,322

3.47

1.03

0.93-1.14

PROM

3,372

5.60

2,975

6.62

1.19

0.97-1.47

24-36 wks: Iatrogenic

35,750

9.72

59,610

8.20

0.84*

0.81-0.88

Spontaneous

31,396

10.3

27,370

9.36

0.92*

0.87-0.97

PROM

8,180

19.8

7,337

19.0

0.95

0.88-1.03


†Neonatal mortality or serious neonatal morbidity included (neonatal death, 5-minute Apgar score ≤3, neonatal seizures or assisted ventilation for ≥30 minutes).

*p-value < 0.05

Births with missing information about serious neonatal morbidity were excluded. Births recorded on new birth certificates in 2004-05 were excluded due to a different definition of assisted ventilation.

Lisonkova et al. BMC Pregnancy and Childbirth 2011 11:39   doi:10.1186/1471-2393-11-39

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