The length of active labor in normal pregnancies

doi:10.1016/0029-7844(95)00423-8

Obstetrics & Gynecology

Volume 87, Issue 3, March 1996, Pages 355-359

https://doi.org/10.1016/0029-7844(95)00423-8 Get rights and content

Objective:

To measure the length of active labor (first and second stages) in a low-risk population of non-Hispanic white, Hispanic, and American Indian women, and to identify any differences among these ethnic groups.

Methods:

Descriptive statistics are presented for 1473 low-risk women at term who delivered at the University of New Mexico Hospital. Data examined by ethnicity included demographics, intrapartum care and complications, and duration of the active-phase first stage (4 cm to complete cervical dilatation) and second stage (complete cervical dilatation to delivery) of labor.

Results:

Compared with Friedman's criteria, 20% of these low-risk women had a prolonged active phase of the first stage, and 4% had a prolonged second stage, without excess maternal or infant morbidity. The mean length of active-phase, first-stage labor was 7.7 hours for nulliparas and 5.7 hours for multiparas (statistical limits 19.4 and 13.7 hours, respectively), with no differences according to ethnic group. The mean length of second stage was 53 minutes for nulliparas and 17 minutes for multiparas (statistical limits 147 and 57 minutes, respectively). American Indian nulliparas had significantly shorter second stages than non-Hispanic white women (P < .05).

Conclusion:

Active labor in healthy women lasted longer than is widely appreciated. Upward revision of clinical expectations for the length of active labor is warranted.

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Cited by (122)

New insights on labor progression: a systematic review
2023, American Journal of Obstetrics and Gynecology
The past 20 years witnessed an invigoration of research on labor progression and a change of thinking regarding normal labor. New evidence is emerging, and more advanced statistical methods are applied to labor progression analyses. Given the wide variations in the onset of active labor and the pattern of labor progression, there is an emerging consensus that the definition of abnormal labor may not be related to an idealized or average labor curve. Alternative approaches to guide labor management have been proposed; for example, using an upper limit of a distribution of labor duration to define abnormally slow labor. Nonetheless, the methods of labor assessment are still primitive and subject to error; more objective measures and more advanced instruments are needed to identify the onset of active labor, monitor labor progression, and define when labor duration is associated with maternal/child risk. Cervical dilation alone may be insufficient to define active labor, and incorporating more physical and biochemical measures may improve accuracy of diagnosing active labor onset and progression. Because the association between duration of labor and perinatal outcomes is rather complex and influenced by various underlying and iatrogenic conditions, future research must carefully explore how to integrate statistical cut-points with clinical outcomes to reach a practical definition of labor abnormalities. Finally, research regarding the complex labor process may benefit from new approaches, such as machine learning technologies and artificial intelligence to improve the predictability of successful vaginal delivery with normal perinatal outcomes.
The duration of spontaneous active and pushing phases of labour among 75,243 US women when intervention is minimal: A prospective, observational cohort study
2022, eClinicalMedicine
Friedman's curve, despite acknowledged limitations, has greatly influenced labour management. Interventions to hasten birth are now ubiquitous, challenging the contemporary study of normal labour. Our primary purpose was to characterise normal active labour and pushing durations in a large, contemporary sample experiencing minimal intervention, stratified by parity, age, and body mass index (BMI).
This is a secondary analysis of the national, validated Midwives Alliance of North America 4·0 (MANA Stats) data registry (n = 75,243), prospectively collected between Jan 1, 2012 and Dec 31, 2018 to describe labour and birth in home and birth center settings where common obstetric interventions [i.e., oxytocin, planned cesarean] are not available. The MANA Stats cohort includes pregnant people who intended birth in these settings and prospectively collects labour and birth processes and outcomes regardless of where birth or postpartum care ultimately occurs. Survival curves were calculated to estimate labour duration percentiles (e.g. 10th, 50th, 90th, and others of interest), by parity and sub-stratified by age and BMI.
Compared to multiparous women (n = 32,882), nulliparous women (n = 15,331) had significantly longer active labour [e.g., median 7.5 vs. 3.3 h; 95th percentile 34.8 vs. 12.0 h] and significantly longer pushing phase [e.g., median 1.1 vs. 0.2 h; 95th percentile 5.5 vs. 1.1 h]. Among nulliparous women, maternal age >35 was associated with longer active first stage of labour and longer pushing phase, and BMI >30 kg/m² was associated with a longer active first stage of labour but a shorter pushing phase. Patterns among multiparous women were different, with those >35 years of age experiencing a slightly more rapid active labour and no difference in pushing duration, and those with BMI >30 kg/m² experiencing a slightly longer active labour but, similarly, no difference in pushing duration.
Nulliparous women had significantly longer active first stage and pushing phase durations than multiparous women, with further variation noted by age and by BMI. Contemporary US women with low-risk pregnancies who intended birth in settings absent common obstetric interventions and in spontaneous labour with a live, vertex, term, singleton, non-anomalous fetus experienced labour durations that were often longer than prior characterizations, particularly among nulliparous women. Results overcome prior and current sampling limitations to refine understanding of normal labour durations and time thresholds signaling ‘labour dystocia’.
OHSU Nursing Innovation and OHSU University Shared Resources.
The length of the second stage of labor in nulliparous, multiparous, grand-multiparous, and grand-grand multiparous women in a large modern cohort
2020, European Journal of Obstetrics and Gynecology and Reproductive Biology
The objectives of this study were to characterize the length of the second stage of labor in a large contemporary cohort of women with varying obstetrical histories and to investigate the factors associated with the length of the second stage.
This was a retrospective cohort study conducted at a tertiary medical center. Women with singleton spontaneous vaginal deliveries between the years 2005–2017 were included. The length of the second stage was compared between groups based on obstetrical history and maternal and obstetrical characteristics were evaluated to identify factors associated with the length of the second stage.
There were 100,759 deliveries included in the study. The second stage of labor was longest in nulliparous women with an epidural (median 96 min, interquartile range 53−142 min), which was 57 min longer than in nulliparous women without an epidural. In parous, grand-multiparous, grand-grand multiparous, and women with a prior cesarean delivery, all without an epidural, there was no clinically significant difference in the length of the second stage (median 6−7 min). The length of the second stage was significantly shorter in women delivering preterm compared to women delivering at term. Birthweight, previous cesarean delivery, gestational age, use of epidural analgesia, and induction of labor were all independently positively associated with the length of the second stage, while parity was negatively associated with the length of the second stage.
The median length of the second stage of labor was considerably longer than historically described in nulliparous women and relatively shorter in parous women.
Is Zhang the new Friedman: How should we evaluate the first stage of labor?
2020, Seminars in Perinatology
Citation Excerpt :
However, over the past several decades an increasing number of studies have been conducted to examine labor norms that have described labor as generally lasting longer, on average, than the original Friedman data, and with several different thresholds. In a study of labor norms from the 1990s, Albers et al. found that labor appeared to progress more slowly than described by Friedman and her labor curve as a different shape.17 Subsequently, a study by Zhang, et al. found that the median cervical change did not exceed 1 cm per hour until 5 cm dilation and that at the 95th centile, it could take longer than an hour to change the cervix up until completely dilated.18
Norms used to describe and evaluate the first stage of labor have been historically based upon data from the middle of the twentieth century. More recent data has characterized the normal first stage of labor differently including that the latent phase of labor is longer not transitioning from latent to active labor until about 6 cm of cervical dilation in a majority of women, regardless of parity or whether labor was spontaneous or induced. Additionally, the amount of time that can take for progress to be made in active labor be longer than previously understood. These two factors would lead to a change in management with the diagnosis of arrest of the first stage of labor being made at 6 cm cervical dilation or beyond in the setting of ruptured membranes and no cervical change for at least 4 h of adequate contractions or 6 h of inadequate contractions.
Point-of-care HIV viral load in pregnant women without prenatal care: a cost-effectiveness analysis
2019, American Journal of Obstetrics and Gynecology
Routine cesarean delivery has been shown to decrease mother-to-child-transmission of HIV in women with high viral load greater than 1000 copies/mL; however, women presenting late in pregnancy may not have viral load results before delivery.
Our study investigated the costs and outcomes of using a point-of-care HIV RNA viral load test to guide delivery compared with routine cesarean delivery for all in the setting of unknown viral load.
A decision-analytic model was constructed using TreeAge software to compare HIV RNA viral load testing vs routine cesarean delivery for all in a theoretical cohort of 1275 HIV-positive women without prenatal care who presented at term for delivery, the estimated population of HIV-positive women without prenatal care in the United States annually. TreeAge Pro software is used to build decision trees modeling clinical problems and perform cost-effectiveness, sensitivity, and simulation analysis to identify the optimal outcome. The average cost per test was $15.22. To examine the downstream impact of a cesarean delivery and because most childbearing women in the United States will deliver 2 children, we incorporated a second pregnancy and delivery in the model. Primary outcomes were mother-to-child transmission, delivery mode, cesarean delivery–related complications, cost, and quality-adjusted life years. Model inputs were derived from the literature and varied in sensitivity analyses. The cost-effectiveness threshold was $100,000/quality-adjusted life year.
Measuring viral load resulted in more HIV-infected neonates than routine cesarean delivery for all due to viral exposure during more frequent vaginal births in this strategy. There were no observed maternal deaths or differences in cesarean delivery–related complications. Quantifying viral load increased cost by $3,883,371 and decreased quality-adjusted life years by 63 compared with routine cesarean delivery for all. With the threshold set at $100,000/quality-adjusted life year, the viral load test is cost-effective only when the vertical transmission rate in women with high viral load was below 0.68% (baseline: 16.8%) and when the odds ratio of vertical transmission with routine cesarean delivery for all compared with vaginal delivery was above 0.885 (baseline: 0.3).
For HIV-infected pregnant women without prenatal care, quantifying viral load to guide mode of delivery using a point-of-care test resulted in increased costs and decreased effectiveness when compared with routine cesarean delivery for all, even after including downstream complications of cesarean delivery.
Duration of spontaneous labour in ‘low-risk’ women with ‘normal’ perinatal outcomes: A systematic review
2018, European Journal of Obstetrics and Gynecology and Reproductive Biology
Citation Excerpt :
From 5911 citations screened, 193 papers were selected for full-text review. Thirty-seven studies evaluating the duration of labour in 203,898 women met our inclusion criteria [3,7–9,11,12,16–46]. Thirty-two (75,081 women) reported the outcomes for nulliparous women and 29 (117,829 women) for parous women.
Despite decades of research, the concept of normality in labour in terms of its progression and duration is not universal or standardized. However, in clinical practice, it is important to define the boundaries that distinguish what is normal from what is abnormal to enable women and care providers have a shared understanding of what to expect and when labour interventions are justified.
To synthesise available evidence on the duration of latent and active first stage and the second stage of spontaneous labour in women at low risk of complications with ‘normal’ perinatal outcomes.
PubMed, EMBASE, CINAHL, POPLINE, Global Health Library, and reference lists of eligible studies.
Observational studies and other study designs.
Four authors extracted data on: maternal characteristics; labour interventions; duration of latent first stage, active first stage, and second stage of labour; and the definitions of onset of latent and active first stage, and second stage where reported. Heterogeneity in the included studies precluded meta-analysis and data were presented descriptively.
Thirty-seven studies reporting the duration of first and/or second stages of labour for 208,000 women met our inclusion criteria. Among nulliparous women, the median duration of active first stage (when the starting reference point was 4 cm) ranged from 3.7–5.9 h (95th percentiles: 14.5–16.7 h). With active phase starting from 5 cm, the median duration was from 3.8–4.3 h (95th percentiles: 11.3–12.7 h). The median duration of second stage ranged from 14 to 66 min (95th percentiles: 65–138 min) and from 6 to 12 min (95th percentiles: 58–76 min) in nulliparous and parous women, respectively. Sensitivity analyses excluding first and second stage interventions did not significantly impact on these findings
The duration of spontaneous labour in women with good perinatal outcomes varies from one woman to another. Some women may experience labour for longer than previously thought, and still achieve a vaginal birth without adverse perinatal outcomes. Our findings question the rigid limits currently applied in clinical practice for the assessment of prolonged first or second stage that warrant obstetric intervention.

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The length of active labor in normal pregnancies

Objective:

Methods:

Results:

Conclusion:

Br J Obstet Gynaecol

J Reprod Med

Obstet Gynecol

Am J Obstet Gynecol

Br J Obstet Gynaecol

Br J Obstet Gynaecol

Human labor and birth

Human labor and birth

The graphic analysis of labor

Am J Obstet Gynecol

Maternity and neonatal nursing: Family-centered care

Nurse-midwifery

Normal cervical dilatation pattern in late pregnancy and labor

Am J Obstet Gynecol

Monitoring the progress of labour

Obstetric characteristics in different racial groups

Br J Obstet Gynaecol