A graphicostatistical analysis

Friedman, Emanuel A.

doi:10.1097/00006250-195612000-00007

Cited by 282 publications

(139 citation statements)

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“…Shortly thereafter in 1956, Friedman presented similar results for 500 multiparae at term, using a presumably similar methodology. 3 In this analysis, he showed that multiparae have a shorter first and second stage of labour than primirarae. Furthermore, among multiparae, the latent phase shortened with increasing parity.…”

Section: Friedman's Labour Curvementioning

confidence: 95%

“…In the 1950s, Emanuel Friedman described the first comprehensive method of evaluating labour in clinical practice. [1][2][3] In this landmark series of publications, Friedman described the relationship between the duration of labour and cervical dilation as a sigmoid curve and outlined a tool for following labour progression and for identifying abnormal labour. This curve, commonly referred to as the Friedman curve, consisted of two stages.…”

Section: Introductionmentioning

confidence: 99%

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Methodological challenges in studying labour progression in contemporary practice

Vahratian

Troendle

Siega‐Riz

et al. 2006

Paediatric Perinatal Epid

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In the 1950s, Emanuel Friedman described the first comprehensive method of evaluating labour in clinical practice. In this landmark work, Friedman described the relationship between the duration of labour and cervical dilation as a sigmoid curve and outlined a tool for following labour progression and for identifying abnormal labour. His definitions of labour protraction and arrest continue to be applied in contemporary obstetric practice, although there have been considerable changes since in the clinical management of labour and delivery. This paper provides an overview of Friedman's work, addresses various methodological challenges in studying labour progression, and describes the utility of more advanced statistical methods for studying labour progression, such as survival analysis, compared with other approaches. Additional research that utilises and refines such methods will provide greater insight into labour progression and may assist in updating the diagnostic criteria for labour protraction and arrest disorders in contemporary obstetric practice. Moreover, such detailed information could have important clinical implications towards reducing the rate of primary caesarean delivery in the United States.

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Section: Friedman's Labour Curvementioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Methodological challenges in studying labour progression in contemporary practice

Vahratian

Troendle

Siega‐Riz

et al. 2006

Paediatric Perinatal Epid

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“…Since Friedman's seminal work in the 1950s, vaginal examination has formed the basis for assessing progress in labor, with cervical dilatation, fetal head position and fetal head descent (station) all recorded at each assessment and plotted serially on a graph over time (partogram) [1][2][3][4] . However, vaginal examination is subjective, imprecise, uncomfortable for women and associated with infection, leading to calls for research into new approaches for assessing progress in labor [5][6][7][8][9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Comparison of different methods of measuring angle of progression in prediction of labor outcome

Frick

Kostiv

Vojtassakova

et al. 2020

Ultrasound in Obstet & Gyne

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Objectives First, to compare the manual sagittal and parasagittal and automated parasagittal methods of measuring the angle of progression (AoP) by transperineal ultrasound during labor, and, second, to develop models for the prediction of time to delivery and need for Cesarean section (CS) for failure to progress (FTP) in a population of patients undergoing induction of labor. Methods This was a prospective observational study of transperineal ultrasound in a cohort of 512 women with a singleton pregnancy undergoing induction of labor. A random selection of 50 stored images was assessed for inter‐ and intraobserver reliability of AoP measurements using the manual sagittal and parasagittal and automated parasagittal methods. In cases of vaginal delivery, univariate linear, multiple linear and quantile regression analyses were performed to predict time to delivery. Univariate and multivariate binomial logistic regression analyses were performed to predict CS for FTP in the first stage of labor. Results The intraclass correlation coefficient (ICC) for the manual parasagittal method for a single observer was 0.97 (95% CI, 0.95–0.98) and for two observers it was 0.96 (95% CI, 0.93–0.98), indicating good reliability. The ICC for the sagittal method for a single observer was 0.93 (95% CI, 0.88–0.96) and for two observers it was 0.74 (95% CI, 0.58–0.84), indicating moderate reliability for a single observer and poor reliability between two observers. Bland–Altman analysis demonstrated narrower limits of agreement for the manual parasagittal approach than for the sagittal approach for both a single and two observers. The automated parasagittal method failed to capture an image in 19% of cases. The mean difference in AoP measurements between the sagittal and manual parasagittal methods was 11°. In pregnancies resulting in vaginal delivery, 54% of the variation in time to delivery was explained in a model combining parity, epidural and syntocinon use during labor and the sonographic findings of fetal head position and AoP. In the prediction of CS for FTP in the first stage of labor, a model which combined maternal factors with the sonographic measurements of AoP and estimated fetal weight was superior to one utilizing maternal factors alone (area under the receiver‐operating‐characteristics curve, 0.80 vs 0.76). Conclusions First, the method of measuring AoP with the greatest reliability is the manual parasagittal technique and future research should focus on this technique. Second, over half of the variation in time to vaginal delivery can be explained by a model that combines maternal factors, pregnancy characteristics and ultrasound findings. Third, the ability of AoP to provide clinically useful prediction of CS for FTP in the first stage of labor is limited. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

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“…Only recently was it realized that these points not only relate to duration of labor but may also influence it, possibly in a causal manner (9). Other widely publicized attempts have been to subdivide first stage labor into a latent and active phase (10,11), an approach that adds yet another ill-defined time point to the equation and resolves none of its vagaries, with latent phases ranging from 1 to 44 hours in nulliparas (10). The end of first stage labor has known similar approaches, with O'Driscoll et al, for example, arguing that second stage labor consists of two distinct phases, the first of which is only the natural extension of first stage labor (7).…”

mentioning

confidence: 99%

“…Within this array of studies people have, not surprisingly, come up with widely varying durations. Two recent studies in American hospitals (12,13) have even shaken Friedman's classical studies on labor duration (10,11), which have been transcribed from one obstetric textbook to another for decades. Yet, there appear to be no studies on labor duration in "natural circumstances" relatively free of the many interventions that currently pervade labor ward policies.…”

mentioning

confidence: 99%

Influence of Fixed and Time‐Dependent Factors on Duration of Normal First Stage Labor

Groß

Drobnič

Keirse

2005

Birth

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With the exception of parity, events occurring during labor and their timing have a greater influence on the duration of first stage spontaneous labor than elements which are immutable at the onset of labor. Trials of interventions to influence the duration of labor need to consider not only whether the intervention was applied or not, but also when it was applied, if cause-effect relationships are to become properly understood.

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A graphicostatistical analysis

Cited by 282 publications

References 0 publications

Methodological challenges in studying labour progression in contemporary practice

Methodological challenges in studying labour progression in contemporary practice

Comparison of different methods of measuring angle of progression in prediction of labor outcome

Influence of Fixed and Time‐Dependent Factors on Duration of Normal First Stage Labor

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