Residency · Residency · Obstetrics Gynecology
Normal Labor Management and Partogram Use
Stages of Labor
First Stage
The first stage of labor is divided into two phases. The latent phase extends from the onset of regular contractions to 6 cm dilation. Its duration varies widely and may last more than 20 hours in nulliparous women. Cervical dilation during this phase is slow and gradual, and a prolonged latent phase alone is not an indication for admission unless membranes are ruptured or other concerns exist. The active phase extends from 6 cm to complete dilation at 10 cm. It is more predictable, with faster cervical change. Importantly, the contemporary definition places the beginning of active labor at 6 cm, based on the work of Zhang et al., rather than at 4 cm as defined by Friedman.
Second Stage
The second stage begins at complete dilation and ends with delivery of the infant. Acceptable duration is up to 3 hours without an epidural or 4 hours with an epidural in nulliparous women, and up to 2 hours without or 3 hours with an epidural in multiparous women. Extended durations may be acceptable if progress is being made and fetal status remains reassuring.
Third Stage
The third stage extends from delivery of the infant to delivery of the placenta. Normal duration is 5 to 30 minutes. The third stage is considered prolonged after 30 minutes, at which point the risk of hemorrhage increases. Active management of the third stage is recommended.
Friedman vs. Contemporary Labor Curves
Friedman Curve (1954)
The Friedman curve, published in 1954, defined active labor as beginning at 4 cm dilation with expected dilation rates of at least 1.2 cm per hour in nulliparous women and at least 1.5 cm per hour in multiparous women. This curve formed the basis for diagnosing arrest disorders for decades and led to earlier intervention and higher cesarean delivery rates.
Zhang/Contemporary Labor Curve
The Zhang labor curve, based on Consortium on Safe Labor data from more than 60,000 women, produced several key findings that changed practice. Active labor does not reliably begin until 6 cm. From 4 to 6 cm, dilation can be very slow, especially in nulliparous women, and this slow progress is not an indication for cesarean delivery. The rate of dilation accelerates only after 6 cm. As a result, 6 cm became the new threshold for diagnosing active-phase arrest. These findings were endorsed by ACOG and SMFM in their 2014 consensus statement on Safe Prevention of the Primary Cesarean.
Updated Arrest Definitions (ACOG/SMFM)
Under the updated definitions, there is no universally defined duration for latent phase arrest, and prolonged latent phase alone is not an indication for cesarean delivery. Active phase arrest in the first stage requires at least 6 cm dilation with ruptured membranes and either no cervical change for 4 or more hours with adequate contractions (Montevideo units of 200 or greater) or 6 or more hours with inadequate contractions despite oxytocin augmentation. Second stage arrest is defined as no progress for 3 or more hours with an epidural or 2 or more hours without in nulliparous women, and 2 or more hours with or 1 or more hours without in multiparous women. Extension of these time limits should be considered if progress is being made.
| Stage | Arrest Definition | Nulliparous | Multiparous |
|---|---|---|---|
| Active phase (first stage) | No cervical change with adequate contractions (≥200 MVU) and ruptured membranes | ≥4 hours (adequate ctx) or ≥6 hours (inadequate ctx) | Same criteria |
| Second stage | No progress (descent or rotation) | ≥3 hours with epidural; ≥2 hours without | ≥2 hours with epidural; ≥1 hour without |
| Latent phase | No defined arrest duration | Not an indication for cesarean | Not an indication for cesarean |
<image>Comparison graph of the Friedman labor curve versus the Zhang contemporary labor curve, showing cervical dilation (y-axis) over time (x-axis), with the Friedman curve beginning active phase at 4 cm with a steep slope and the Zhang curve showing a gradual acceleration that begins at 6 cm</image>
Partogram Use
Purpose
A partogram is a graphical record of labor progress plotted against time. It allows early identification of slow progress or arrest. The WHO partogram is widely used globally, though it is less commonly used in US practice.
Components
The partogram plots cervical dilation against time and fetal descent (station) against time. It also records contraction frequency and duration, fetal heart rate, maternal vital signs, and medications administered.
Alert and Action Lines
The alert line represents the expected rate of dilation, typically 1 cm per hour from the active phase. The action line, placed 4 hours to the right of the alert line, prompts intervention such as amniotomy or oxytocin when crossed. The WHO modified partogram begins plotting at 4 cm.
Evidence
Partograms reduce prolonged labor and the need for oxytocin augmentation in resource-limited settings. In well-resourced settings, their value is less clear, but they remain useful as teaching and communication tools. Partograms must be interpreted with contemporary labor curves in mind rather than Friedman criteria.
Admission Criteria and Triage
Criteria for Admission in Labor
Criteria warranting admission include regular painful contractions with documented cervical change, active phase labor (typically 6 cm or greater), ruptured membranes, and any complication requiring monitoring (bleeding, non-reassuring fetal heart rate, or preeclampsia). Premature admission of latent-phase patients increases intervention rates, including artificial rupture of membranes, oxytocin use, and cesarean delivery.
Assessment at Triage
Triage assessment includes cervical examination (dilation, effacement, station, presenting part, and position), fetal heart rate tracing (a 20-minute reactive strip at minimum), contraction pattern, membrane status (ruptured versus intact), and review of GBS status.
Active Management of Labor
Definition
Active management of labor is a protocol-based approach originally developed as the Dublin protocol. It includes strict diagnostic criteria for labor onset, early amniotomy, early oxytocin augmentation if dilation is less than 1 cm per hour in the active phase, and continuous one-to-one nurse support. The goal is to ensure delivery within 12 hours.
Evidence
Active management reduces labor duration but does not clearly reduce cesarean rates. The continuous support component may be the most important element. Modified versions of the protocol are used in many institutions.
Intrapartum Management
Support During Labor
Continuous labor support from a doula, nurse, or partner is associated with shorter labor, fewer cesarean deliveries, fewer epidurals, and higher maternal satisfaction. Ambulation and position changes are encouraged, as there is no evidence of benefit from bed rest during labor. Oral intake of clear liquids is safe during labor; solid food intake is institution-dependent.
Amniotomy
Amniotomy is the artificial rupture of membranes using an amniohook. Indications include augmentation of slow labor and the need for internal monitoring. Prerequisites include vertex presentation, adequate cervical dilation (typically 3 to 4 cm or greater), and an engaged presenting part. Risks include cord prolapse (rare; the presenting cord should be checked before performing amniotomy) and infection with prolonged rupture of membranes. Routine amniotomy in spontaneous labor does not reduce the cesarean rate but shortens labor by approximately 1 to 2 hours.
Oxytocin Augmentation
Oxytocin augmentation is indicated for inadequate labor progress, such as slow dilation or hypotonic contractions. The low-dose protocol starts at 1 to 2 mU/min and increases by 1 to 2 mU/min every 30 to 40 minutes. The high-dose protocol starts at 4 to 6 mU/min and increases by 4 to 6 mU/min every 15 to 40 minutes. The goal is 3 to 5 contractions in 10 minutes with Montevideo units of 200 or greater. The dose is titrated to achieve an adequate contraction pattern while avoiding tachysystole, defined as more than 5 contractions in 10 minutes. Tachysystole is managed by reducing or stopping oxytocin, lateral positioning, administering an IV fluid bolus, and considering terbutaline.
<image>Partogram example showing cervical dilation (circles) and fetal station (X marks) plotted against time in hours for a nulliparous patient, with annotations showing latent phase, active phase onset at 6 cm, amniotomy, oxytocin initiation, and second stage entry</image>
Monitoring in Labor
Fetal Heart Rate Monitoring
Continuous electronic fetal monitoring (EFM) is standard in most US institutions. Intermittent auscultation is an acceptable alternative in low-risk patients, performed every 15 to 30 minutes in the first stage and every 5 to 15 minutes in the second stage.
Maternal Monitoring
Maternal vital signs are assessed every 1 to 4 hours, with more frequent monitoring when an epidural is in place, oxytocin is infusing, or complications are present. Fluid balance (IV fluids, oral intake, and urine output) and pain assessment and management are monitored throughout labor.
Clinical Pearls
Do not diagnose active-phase arrest before 6 cm. Cesarean delivery for "failure to progress" at 4 to 5 cm is a leading cause of preventable primary cesareans.
Allow adequate time: at least 4 hours of adequate contractions (or at least 6 hours of augmented labor) should elapse before diagnosing arrest in the active phase.
Continuous labor support is one of the most effective interventions to improve labor outcomes and reduce cesarean rates.
The contemporary labor curve permits slower dilation from 4 to 6 cm than the Friedman curve. Patience in this zone prevents unnecessary interventions.
Second-stage duration limits should be considered guidelines, not mandates. Duration can be extended if descent is progressing and fetal status is reassuring.
Amniotomy alone shortens labor but does not reduce the cesarean rate. It is most useful as an adjunct to oxytocin.
Avoid admitting patients in latent labor when possible. Early admission is associated with increased interventions without improved outcomes.
References
- ACOG/SMFM Obstetric Care Consensus No. 1: Safe Prevention of the Primary Cesarean Delivery (2014, reaffirmed 2020)
- Zhang J et al. Contemporary patterns of spontaneous labor with normal neonatal outcomes. Obstet Gynecol. 2010;116:1281-1287
- Friedman EA. Primigravid labor; a graphicostatistical analysis. Obstet Gynecol. 1955;6:567-589
- WHO. WHO Labour Care Guide. 2020
- Hodnett ED et al. Continuous support for women during childbirth. Cochrane Database Syst Rev. 2017
- Clark SL et al. Oxytocin: new perspectives on an old drug. Am J Obstet Gynecol. 2009;200:35.e1-6
