The impact of the active management of risk in pregnancy at term on birth outcomes: a randomized clinical trial

Abstract

Objective: The purpose of this study was to compare birth outcomes that result from the active management of risk in pregnancy at term (AMOR-IPAT) to those outcomes that result from standard management.

Study design: This was a randomized clinical trial with 270 women of mixed parity. AMOR-IPAT used preventive labor induction to ensure delivery before the end of an estimated optimal time of delivery. Rates of 4 adverse obstetric events and 2 composite measures were used to evaluate birth outcomes.

Results: The AMOR-IPAT-exposed group had a similar cesarean delivery rate (10.3% vs 14.9%; P = .25), but a lower neonatal intensive care unit admission rate (1.5% vs 6.7%; P = .03), a higher uncomplicated vaginal birth rate (73.5% vs 62.8%; P = .046), and a lower mean Adverse Outcome Index score (1.4 vs 8.6; P = .03).

Conclusion: AMOR-IPAT exposure improved the pattern of birth outcomes. Larger randomized clinical trials are needed to explore further the impact of AMOR-IPAT on birth outcomes and to determine the best methods of preventive labor induction.

Figure 1

Study Group Development – This figure demonstrates the flow of subjects throughout the study.

Figure 2

Survival Analysis of Timing of Delivery by Study Group: Number of weeks beyond 37 weeks 0 days gestation at the time of delivery – This figure demonstrates the continuous nature of earlier gestational age at delivery in the exposed group as compared to the non-exposed group.

Figure 3

Figure 3a. Distribution of gestational age at delivery by study group – This figure demonstrates the timing of delivery by half weeks of gestation in the two study groups. Figure 3b. Distribution of mode of labor onset by gestational age and study group - This figure demonstrates the timing of labor induction and spontaneous labor by half weeks of gestation in the two study groups. Figure 3c. Distribution of type of nursery admission by gestational age and study group - This figure demonstrates the timing of NICU admission by half weeks of gestation in the two study groups.

Appendix 1

AMOR-IPAT - UL-OTD Calculation Sheet - This figure outlines the scoring sheet used to estimate, for each study subject, the upper limit of the optimal time of delivery.

Appendix 4

Average gestational age at delivery as a function of Yeager Group - This figure demonstrates the relationship between magnitude of risk of cesarean delivery (measured in Yeager Units [or days subtracted from 41 weeks 0 days gestation] and mean gestational age at delivery in the two study groups In the exposed group, greater risk resulted in earlier mean gestational age at delivery than in the non-exposed group.