Document Detail

Reassessing the labor curve in nulliparous women.
MedLine Citation:
PMID:  12388957     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: Our purpose was to examine the pattern of labor progression in nulliparous parturients in contemporary obstetric practice. STUDY DESIGN: We extracted detailed labor data from 1329 nulliparous parturients with a term, singleton, vertex fetus of normal birth weight after spontaneous onset of labor. Cesarean deliveries were excluded. We used a repeated-measures regression with a 10th-order polynomial function to discover the average labor curve under contemporary practice. With use of an interval-censored regression with a log normal distribution, we also computed the expected time interval of the cervix to reach the next centimeter, the expected rate of cervical dilation at each phase of labor, and the duration of labor for fetal descent at various stations. RESULTS: Our average labor curve differs markedly from the Friedman curve. The cervix dilated substantially slower in the active phase. It took approximately 5.5 hours from 4 cm to 10 cm, compared with 2.5 hours under the Friedman curve. We observed no deceleration phase. Before 7 cm, no perceivable change in cervical dilation for more than 2 hour was not uncommon. The 5th percentiles of rate of cervical dilation were all below 1 cm per hour. The 95th percentile of time interval for fetal descent from station +1/3 to +2/3 was 3 hours at the second stage. CONCLUSION: Our results suggest that the pattern of labor progression in contemporary practice differs significantly from the Friedman curve. The diagnostic criteria for protraction and arrest disorders of labor may be too stringent in nulliparous women.
Jun Zhang; James F Troendle; Michael K Yancey
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of obstetrics and gynecology     Volume:  187     ISSN:  0002-9378     ISO Abbreviation:  Am. J. Obstet. Gynecol.     Publication Date:  2002 Oct 
Date Detail:
Created Date:  2002-10-21     Completed Date:  2002-11-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370476     Medline TA:  Am J Obstet Gynecol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  824-8     Citation Subset:  AIM; IM    
Division of Epidemiology, Statistics, and Prevention Research, National Institute of Child Health and Human Development/NIH, Building 6100, Room 7B03, Bethesda, MD 20892, USA.
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MeSH Terms
Labor Stage, First
Labor Stage, Second
Labor, Obstetric / physiology*
Time Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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