Association of Oxytocin Rest During Labor Induction of Nulliparous Women With Mode of Delivery

Cervical ripening and labour induction: A critical review of the available methods

Induction of labour is one of the most common interventions experienced by pregnant women. There are two overlapping components to labour induction, which include cervical ripening and the initiation of regular contractions. A large number of clinical studies have been conducted for evaluating the methods used for induction of labour, their effectiveness and safety, and pregnancy outcomes. Randomised controlled trials (RCTs) provide the strongest form of evidence for clinical practice. These data are brought together in systematic reviews and have been incorporated into national and international guidelines. Despite this, there is considerable variation in the recommendations between guidelines. Heterogeneity between studies, inconsistency in the definitions of trial outcomes, and underpowered sample size contribute to the difficulty in making robust recommendations. There are pharmacological and non-pharmacological approaches that can be compared with each other and with placebo or no treatment. There are also complementary therapies that may appeal to women but lack evidence of their effectiveness. These issues have been addressed in the current chapter, with a critical review of the research evidence presented in clinical trials and systematic reviews.

Towards an evidence-based approach to optimize the success of labour induction

Induction of labour is a two-step process involving cervical ripening and the initiation of uterine contractions, with the goal of achieving vaginal birth. To optimize the chance of a safe and timely vaginal birth, the process of induction of labour should be evidence based and individualized to the given person and situation. In this study, we lay out a framework for how this should be done, emphasizing on careful clinical assessment and planning, flexibility in the strategy of induction, patience during the ripening and latent phases of labour, and thoughtful consideration regarding changing the strategy if active labour is not initially achieved. The goal of this review is to present the current evidence on this topic in the form of a user-friendly protocol that can be easily adapted to institutional practice.

Predicting Postpartum Hemorrhage After Low-Risk Vaginal Birth by Labor Characteristics and Oxytocin Administration

OBJECTIVE

To determine the odds of postpartum hemorrhage (PPH) in low-risk women who gave birth vaginally and were exposed to different durations and dosages of oxytocin across a range of labor durations during spontaneous or induced labor.

DESIGN

A retrospective cross-sectional analysis of data from the Consortium for Safe Labor.

SETTING

Data were gathered from 12 clinical institutions across the United States from 2002 to 2008.

PARTICIPANTS

After exclusion of high-risk conditions associated with PPH, we examined data from 27,072 women who gave birth vaginally.

METHODS

PPH was defined as estimated blood loss of greater than 500 ml at the time of birth and/or a diagnostic code for PPH before hospital discharge. We included covariates were if they were associated with oxytocin use and PPH and did not mediate oxytocin use. We used regression models to determine the likelihood of PPH overall and within the induced and spontaneous labor groups separately. We used subgroup analyses within specific durations of labor to clarify the findings.

RESULTS

The overall rate of PPH was 3.9%. Women with induced labor experienced PPH more frequently than women who labored spontaneously. Labor augmentation was associated with greater adjusted odds for PPH when oxytocin was infused for more than 4 hours. Longer duration of spontaneous labor and the second stage of labor did not change this association. Oxytocin use during labor induction increased the odds for PPH when administered for more than 7 hours. The odds further increased when induction lasted longer than 12 hours and/or the second stage of labor was longer than 3 hours.

CONCLUSION

Strategies for judicious oxytocin administration may help mitigate PPH in low-risk women having vaginal birth.