IN REVIEW
What is the Slowest-Yet-Normal Cervical Dilation Rate Among Nulliparous Women With Spontaneous Labor Onset?

https://doi.org/10.1111/j.1552-6909.2010.01154.xGet rights and content

ABSTRACT

Objective

To integrate research literature that has provided insights into the cervical dilation rate that may best describe the slowest-yet-normal dilation rate among nulliparous women when beginning with criteria commonly associated with active labor onset.

Data Sources

A literature search from 1950 through 2008 was conducted using the Medline electronic database, reference lists from identified articles, and other key references.

Study Selection

Research reports written in English with a focus on the cervical dilation and/or labor duration of low-risk, nulliparous women with spontaneous labor onset.

Data Extraction

Classic and contemporary research literature was reviewed and organized under the following subheadings: Friedman Studies, Partograph Studies, Active Management of Labor Studies, Additional Studies.

Data Synthesis

An integrative review of the literature approximated the slowest-yet-normal cervical dilation rate for nulliparous women when beginning with criteria commonly associated with active labor.

Conclusions

The slowest-yet-normal linear dilation rate approximates 0.5 cm/hour for low-risk, nulliparous women with spontaneous labor onset when starting at dilatations traditionally associated with active labor onset. However, this linear rate must be evaluated judiciously in light of the physiological acceleration of dilation that occurs during typical labor. Given this, cervical dilation for this population is likely slower than 0.5 cm/hour in earlier active labor and faster in more advanced active labor. Faster dilation expectations (e.g., 1 cm/hour) likely contribute to an overdiagnosis of dystocia (“slow, abnormal progression of labor”) in contemporary practice and, subsequently, to an overuse of interventions aimed at accelerating labor progress.

Section snippets

Background

Clinical expectations of cervical dilation among nulliparous women continue to be heavily influenced by the research of Dr. Emanuel Friedman, which began more than a half-century ago. Additional knowledge about dilation rates during labor for this population can also be gleaned from the classic publications borne from two of the most widespread labor assessment/management strategies: the partograph and the active management of labor protocol. More contemporary work has also been done in this

Discussion

When beginning with criteria commonly associated with active labor onset (e.g., 3 to 5 cm and regular contractions), the extant research indicates that the slowest-yet-normal, linear dilation rate approximates 0.5 cm/hour for low-risk, nulliparous women with spontaneous labor onset. This rate is achievable for approximately 80% to 90% of this population. Commonly applied linear expectations such as 1 cm/hour are unrealistically fast.

Consideration must be given to two specific realities before a

Conclusion

Our review of the relevant extant research concludes that the slowest-yet-normal linear dilation rate approximates 0.5 cm/hour for low-risk, nulliparous women with spontaneous labor onset when starting at dilatations traditionally associated with active labor onset. However, this linear rate includes the slower rate of earlier active labor and the physiological acceleration of dilation that is typical of advancing labor.

Conflict of Interest Disclosure

Nancy K. Lowe is the editor of JOGNN. She was excluded from the peer review and editorial decision for this article.

Acknowledgments

Initiated under a Ruth L. Kirschstein National Research Service Fellowship Award, National Institute of Nursing Research, NIH 1 F31 NR010054.

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