From the Guidelines
Latent labor is defined as the initial phase of the first stage of labor, where cervical dilatation is negligible or absent, and the rate of dilatation is relatively flat, typically occurring before the onset of the active phase 1.
Key Characteristics of Latent Labor
- The cervix typically dilates from 0 to 3-4 centimeters during this phase.
- Contractions may be 5-30 minutes apart, lasting about 30-45 seconds each.
- Latent labor can last anywhere from a few hours to several days, particularly in first-time mothers.
- Contractions during latent labor are often manageable without medical pain relief.
Importance of Latent Labor
- This phase serves to gradually prepare the cervix for the more intense active labor phase by softening, thinning (effacement), and beginning dilation.
- Latent labor is physiologically important as it allows the body to gradually transition into the more demanding active phase of labor.
Management of Latent Labor
- Healthcare providers generally recommend that women remain at home during latent labor, using comfort measures like walking, warm showers, or position changes, while staying hydrated and resting when possible.
- 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 contractions inconsistently increase in intensity, frequency, and duration over the course of the first stage 1.
From the Research
Definition of Latent Labour
The latent phase of labor is a complex and not completely understood phenomenon in modern science 2. It is defined as the period from the initiation of labor to the onset of the active phase, during which the cervix undergoes rapid remodeling and preparation for dilation 3.
Characteristics of Latent Labour
- The latent phase is characterized by a slower progression than previously thought, with the transition to active labor occurring at around 6 cm of cervical dilatation, regardless of parity or labor type 4.
- The cervix softens, becomes thinner, and more compliant during this phase, with modest dilation 3.
- The duration of the latent phase can only be estimated, as the margins are not always precisely identifiable, and can normally extend for many hours, with a limit of approximately 20 hours in nulliparas and 14 hours in multiparas 3.
Factors Associated with Prolonged Latent Phase
- Deficient prelabor or intrapartum cervical remodeling
- Excessive maternal analgesia or anesthesia
- Maternal obesity
- Chorioamnionitis 3
- Cervical contractions in response to myometrial activity, which may indicate incomplete preparation of the cervix for dilation 5
Management of Prolonged Latent Phase
- Augmenting uterine activity with oxytocin
- Providing a sedative-induced period of maternal rest, both of which are equally effective in advancing labor to active phase dilation 3