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Table 3 Rates of labor induction and/or cesarean delivery, perinatal mortality (excluding congenital malformations) and the marginal number needed to treat in order to prevent one perinatal death in various subpopulations, United States, 1995–96 and 1999–2000.

From: Theory of obstetrics: An epidemiologic framework for justifying medically indicated early delivery

Population

Labor induction/cesarean deliveries per 1,000 fetuses

Perinatal deaths*/1,000 fetuses

Number needed to treat (marginal)

 

1995–96

1999–00

Change†

1995–96

1999–00

Change

 

Singletons ≥ 28 weeks, all

339.4

384.5

45.1

3.95

3.64

0.31‡

145

   ≥ 28 weeks, no medical risk factors

294.6

337.7

43.0

2.98

2.68

0.29‡

146

   ≥ 28 weeks, with hypertension

662.4

697.6

35.2

6.96

6.76

0.20

180

   ≥ 28 weeks, with diabetes

532.4

578.4

46.0

6.67

6.49

0.18

257

   ≥ 28 weeks, with hyp. and diabetes

744.6

779.3

34.7

8.83

9.96

-1.13

-31

Twins ≥ 28 weeks, all

636.5

685.3

48.8

12.13

10.63

1.50‡

32

Singletons ≥ 34 weeks, all

338.3

383.2

44.8

2.66

2.42

0.24‡

188

   ≥ 34 weeks, no medical risk factors

294.5

337.5

42.0

2.09

1.86

0.23‡

181

   ≥ 34 weeks, with hypertension

654.1

689.5

35.1

3.91

3.87

0.04

927

   ≥ 34 weeks, with diabetes

533.3

579.8

45.7

5.25

5.14

0.11

403

   ≥ 34 weeks, with hyp. and diabetes

740.9

776.6

35.0

6.86

7.29

-0.43

-81

Twins ≥ 34 weeks, all

634.8

685.9

48.7

6.68

6.16

0.53

92

  1. * excluding perinatal deaths due to congenital malformations
  2. † All temporal changes in labor induction/cesarean delivery rates were statistically significant P < 0.0001.
  3. ‡ Temporal changes in perinatal death rates statistically significant P < 0.0001.
  4. Hypertension includes chronic and pregnancy-associated hypertension and eclampsia (National Center for Health Statistics definitions).