From the Guidelines
The key indicators of labor include an increase in the rate of cervical dilatation, which signals the transition from the latent to the active phase, and this is the most reliable method for prospectively identifying the onset of the active phase and the normality of its progression, as stated in the study by 1. The active phase of labor begins at various degrees of dilatation when the rate of dilatation transitions from the relatively flat slope of the latent phase to a more rapid slope. Key indicators of labor include:
- Cervical changes, such as effacement and dilation, with active labor generally considered when the cervix is dilated to 4-6 centimeters
- Regular uterine contractions, which typically start mild and infrequent but gradually become stronger, more painful, and occur at consistent intervals
- Rupture of membranes, commonly known as "water breaking," which occurs when the amniotic sac tears, releasing clear fluid
- Bloody show, which is the passage of a small amount of blood-tinged mucus, happening when the cervical mucus plug dislodges as the cervix begins to open Other indicators may include:
- Lightening, when the baby drops lower into the pelvis
- Increased pelvic pressure
- Lower back pain
- Gastrointestinal symptoms like nausea or diarrhea These signs help healthcare providers determine if true labor has begun and assess its progression through the first stage (cervical dilation), second stage (pushing and delivery), and third stage (placental delivery), as discussed in the study by 1. It is essential to note that assessing uterine contractions, for example, by palpation or using Montevideo Units, is of limited value in determining if a patient is in the active phase, as stated in the study by 1. The most reliable method for identifying the onset of the active phase is by monitoring the rate of cervical dilatation, which can be done through serial vaginal examinations at least every 2 hours, as recommended in the study by 1.
From the FDA Drug Label
The fetal heart rate, resting uterine tone, and the frequency, duration, and force of contractions should be monitored. The key indicators of labor are:
- Fetal heart rate
- Resting uterine tone
- Frequency of contractions
- Duration of contractions
- Force of contractions 2
From the Research
Key Indicators of Labor
The key indicators of labor include:
- Regular, painful contractions 3
- Cervical dilation and effacement 3, 4, 5
- Uterine contractions 6
- Onset of the latent phase, active phase, and second stage of labor 3, 5
Phases of Labor
The phases of labor are:
- Latent phase: begins with onset of regular, painful contractions and continues until 6 cm of cervical dilation 3
- Active phase: begins at 6 cm of cervical dilation 3
- Second stage: begins at complete cervical dilation and continues to delivery 3, 5
Labor Progress
Labor progress is highly variable and can be affected by several factors, including:
- Cervical dilation on admission 4
- Uterine contractions 6
- Oxytocin administration 3, 4, 6
- Maternal and fetal circumstances 5
Abnormal Labor Patterns
Abnormal labor patterns include: