Stages of Labor and Childbirth
Overview of Labor Stages
Labor is divided into three distinct stages: the first stage (from onset of labor to complete cervical dilation), the second stage (from complete dilation to delivery of the baby), and the third stage (from delivery of the baby to delivery of the placenta). 1
First Stage of Labor
The first stage consists of two phases: the latent phase and the active phase. 1
Latent Phase
- Begins with the onset of regular uterine contractions and ends when cervical dilation accelerates 2
- Characterized by a relatively flat or negligible slope of cervical dilation 2
- Much slower than previously thought in historical models 3
- Duration is highly variable and cannot be reliably predicted by contraction patterns alone 2
Active Phase
- Begins when the rate of cervical dilation increases from the flat slope of latent phase to more rapid progression, regardless of the specific centimeter of dilation achieved 2, 1
- The transition from latent to active labor typically does not occur until approximately 6 cm of cervical dilation 3
- Identified through serial vaginal examinations performed at least every 2 hours 2, 1
- Normal dilation rates are ≥1.2 cm/hour for nulliparous women and ≥1.5 cm/hour for multiparous women 1, 4
- Most cervical dilation occurs during this phase 2
- Ends with a brief deceleration phase (often undetected) as the cervix approaches complete dilation 2
Management of First Stage
- Regular monitoring of cervical dilation using a partogram 1
- Assessment of uterine contractions 1
- Continuous fetal monitoring 1
- Adequate pain management, with epidural analgesia preferred as it stabilizes cardiac output 1
Common Pitfalls
- Uterine contraction assessment (palpation or Montevideo Units) is of limited value in determining active phase onset, as contractions do not consistently increase in a predictable pattern 2
- The dilatation pattern graphed serially is the only reliable method for prospectively identifying active phase onset 2
Second Stage of Labor
- Begins at complete cervical dilation (10 cm) and ends with delivery of the fetus 1
- Duration should be allowed for 2-3 hours 1
- Can be subdivided into the period before and after maternal expulsive efforts begin 5
Management of Second Stage
- Consider assisted vaginal delivery (forceps or vacuum) if spontaneous delivery cannot be achieved rapidly 1
- Avoid prolonged bearing down efforts to prevent complications 1
Risk Factors for Abnormalities
- Cephalopelvic disproportion 1
- Excessive neuraxial block 1
- Poor uterine contractility 1
- Fetal malpositions or malpresentations 1, 6
- Advanced maternal age 1
- Previous cesarean delivery 1
- Obesity 6
Third Stage of Labor
- Defined as the time period between delivery of the fetus through delivery of the placenta 7
- Normal duration is up to 1 hour if not actively managed 1
- During normal third stage, uterine contractions lead to separation and expulsion of the placenta 7
Evidence-Based Third Stage Care
Current evidence supports abandoning the term "active management of the third stage" as a bundled intervention, and instead implementing specific evidence-based practices termed "third stage care" 7
Recommended Interventions:
- Pharmacologic postpartum hemorrhage prophylaxis with uterotonics 7
- Delayed cord clamping 7
- Early skin-to-skin contact 7
- Controlled cord traction when feasible 7, 8
Interventions to Avoid:
Outcomes with Evidence-Based Care
- Reduced maternal blood loss (mean difference -79.33 mL) 8
- Reduced postpartum hemorrhage >500 mL (relative risk 0.38) 8
- Reduced prolonged third stage (mean difference -9.77 minutes) 8
- Increased risk of nausea and vomiting when ergometrine is used 8
Management of Labor Abnormalities
First Stage Disorders
- Allow at least 12 hours after completion of cervical ripening, membrane rupture, and uterotonic use before considering cesarean delivery for "failed induction" in the latent phase 4
- Interventions for abnormal progression include oxytocin administration, amniotomy, and internal tocodynamometry 6, 3
- Providers should have a low threshold to use these safe and effective interventions 3