Labor Induction and Cesarean Delivery: Rates and Indications in Study Groups Exposed or Not Exposed to Active Management of Risk in Pregnancy at Term (AMOR-IPAT)
| Measure | Exposed (n = 794) | Nonexposed (n = 1,075) | Risk Ratio (95% CI) | P Value |
|---|---|---|---|---|
| CI = confidence interval; ACOG = American College of Obstetricians and Gynecologists; CPD = cephalopelvic disproportion. | ||||
| Note: Values in the Exposed and Nonexposed columns are expressed as percent alone or percent (numerator/denominator). Statistical analyses were performed using χ2 tests (Fisher’s exact test). | ||||
| * No “other” reason for cesarean occurred more than twice in either group. | ||||
| Induction rates | ||||
| Overall induction | 31.4 | 20.4 | 1.37 (1.23–1.52) | <.001 |
| Preventive induction | 21.2 | 8.1 | 1.70 (1.53–1.89) | <.001 |
| Indicated induction | 10.2 | 12.3 | 0.88 (0.74–1.06) | .18 |
| Nulliparous induction | 27.8 (93/334) | 20.6 (100/486) | 1.25 (1.05–1.50) | .02 |
| Multiparous induction | 31.7 (129/407) | 19.3 (96/498) | 1.40 (1.21–1.62) | <.001 |
| Previous cesarean induction | 50.9 (27/53) | 25.3 (23/91) | 1.95 (1.29–2.96) | .002 |
| Induction indications | ||||
| ACOG-approved indication | ||||
| Postdates 41–42 wk | 5.5 | 6.0 | 0.96 (0.76–1.21) | .76 |
| Postdates >42 wk | 0.3 | 0.5 | 0.67 (0.21–2.17) | .71 |
| Preeclampsia | 1.9 | 3.0 | 0.75 (0.49–1.14) | .18 |
| Fetal compromise | 1.4 | 1.5 | 0.96 (0.61–1.52) | 1.00 |
| History of rapid labor | 0.5 | 0.4 | 1.18 (0.59–2.36) | .73 |
| Other | 0.6 | 0.9 | 0.78 (0.38–1.61) | .60 |
| Preventive | ||||
| Impending macrosomia | 7.2 | 2.4 | 1.66 (1.42–1.94) | <.001 |
| Previous cesarean delivery | 2.4 | 0.7 | 1.67 (1.30–2.15) | .005 |
| Impending preeclampsia | 1.4 | 0.4 | 1.74 (1.27–2.37) | .02 |
| Gestational diabetes | 0.6 | 0.6 | 1.07 (0.56–2.05) | 1.00 |
| Other | 9.6 | 4.0 | 1.56 (1.34–1.80) | <.001 |
| Cesarean delivery rates | ||||
| Overall cesarean delivery | 5.3 | 11.8 | 0.56 (0.43–0.73) | <.001 |
| Nulliparous – overall | 8.1 (27/334) | 14.2 (69/486) | 0.66 (0.48–0.92) | .008 |
| Noninduced labor | 7.1 (17/238) | 6.8 (25/368) | 1.03 (0.71–1.51) | .87 |
| Induced labor | 7.5 (7/93) | 26.0 (26/100) | 0.39 (0.20–0.77) | <.001 |
| Planned cesarean delivery | 100 (3/3) | 100 (18/18) | – | |
| Multiparous – overall | 1.2 (5/407) | 4.2 (21/498) | 0.42 (0.19–0.93) | .008 |
| Noninduced labor | 1.1 (3/276) | 1.8 (7/398) | 0.73 (0.28–1.89) | .54 |
| Induced labor | 0.0 (0/129) | 10.4 (10/96) | 0 | .001 |
| Planned cesarean delivery | 100 (2/2) | 100 (4/4) | – | – |
| Previous cesarean delivery – overall | 18.9 (10/53) | 40.7 (37/91) | 0.48 (0.27–0.87) | .01 |
| Noninduced labor | 5.3 (1/19) | 32.7 (18/55) | 0.16 (0.02–1.12) | .03 |
| Induced labor | 7.4 (2/27) | 26.1 (6/23) | 0.42 (0.12–1.43) | .12 |
| Elective repeated cesarean delivery | 100 (7/7) | 100 (13/13) | – | – |
| Cesarean delivery indications | ||||
| CPD/failure to progress | 2.0 (16/794) | 4.7 (51/1,075) | 0.55 (0.36–0.85) | .001 |
| Fetal intolerance | 0.9 (7/794) | 2.7 (29/1,075) | 0.45 (0.23–0.88) | .006 |
| Malpresentation (nonvertex) | 1.3 (10/794) | 2.6 (28/1,075) | 0.61 (0.36–1.05) | .05 |
| Elective repeated | 0.9 (7/794) | 1.2 (13/1,075) | 0.82 (0.45–1.50) | .65 |
| Other* | 0.3 (2/794) | 0.6 (6/1,075) | 0.59 (0.18–1.95) | .48 |