From the Guidelines
The objective signs of labor include regular uterine contractions, cervical changes, and descent of the fetal presenting part into the pelvis, as evidenced by the most recent study in 2023 1.
Key Signs of Labor
- Regular uterine contractions that increase in frequency, duration, and intensity over time, typically starting at 15-20 minutes apart and progressing to 2-3 minutes apart, lasting 60-90 seconds each
- Cervical changes, including cervical effacement (thinning) and dilation, which progresses from 0 to 10 centimeters
- Descent of the fetal presenting part (usually the head) into the pelvis, measured by station relative to the ischial spines
- Rupture of membranes, or "water breaking," which occurs in about 10-15% of women before labor begins, releasing clear amniotic fluid
- Presence of bloody show, a pink or blood-tinged mucus discharge, indicating the expulsion of the mucus plug that sealed the cervix during pregnancy
Importance of Accurate Diagnosis
Accurate diagnosis of labor is crucial to ensure proper management and prevent complications, as highlighted in a study from 2018 1. The active phase of labor, which begins at the end of the latent phase and continues until the cervix is fully dilated, is characterized by a more rapid progression of cervical dilatation, as noted in a 2023 study 1. Another study from 2023 1 emphasizes the importance of uterine contractility in labor, although it acknowledges that quantifying uterine activity is not useful in aiding decision-making about oxytocin administration or dosage.
Clinical Implications
In clinical practice, it is essential to undertake serial vaginal examinations at least every 2 hours to determine when the rate of dilatation increases, signaling the conversion to the active phase, as recommended in a 2023 study 1. This information can help identify potential complications, such as protracted dilatation, arrest of dilatation, or prolonged deceleration phase, and guide management decisions, including the potential need for cesarean delivery, as discussed in a 2023 study 1.
From the Research
Objective Signs of Labor
The objective signs of labor can be identified through various physical and medical indicators. Some of these signs include:
- Cervical effacement: This refers to the thinning of the cervix, which is a key indicator of labor progress 2.
- Fetal station: This is the position of the baby's head in relation to the mother's pelvis, with lower stations indicating a more advanced stage of labor 2.
- Cervical dilation: The opening of the cervix is a critical sign of labor, with active labor typically beginning at around 4-5 cm of dilation.
- Parity: The number of previous births a woman has had can also impact labor progress, with nulliparous women (those having their first baby) often experiencing slower active labor 2.
- Timed cervical exams: Regular exams to measure cervical dilation and effacement can help track labor progress and identify any potential issues 2.