From the Guidelines
To assess uterine contractions during labor, monitor their frequency, duration, and intensity, and evaluate the progression of cervical dilation, as the deceleration phase is a critical component of labor evaluation, existing and widely misunderstood, as noted by 1. When assessing labor contractions, it is essential to consider the frequency, duration, and intensity of the contractions, as well as the physical signs of effective contractions, such as the inability to talk through them, pain radiating from the lower back to the abdomen, and progressive cervical dilation.
- The frequency of contractions can be monitored by timing the interval between the start of one contraction and the start of the next, with early labor typically involving contractions that are 5-30 minutes apart, and active labor contractions occurring every 3-5 minutes.
- The duration of contractions can be assessed by noting how long each contraction lasts, with early labor contractions lasting 30-45 seconds, and active labor contractions lasting 45-60 seconds.
- The intensity of contractions can be subjectively rated on a scale of 1-10 or assessed by placing a hand on the abdomen to feel the firmness, as the uterus becomes hard during a contraction and softens between them, as discussed in 1. The progression of cervical dilation is also a critical component of labor evaluation, as noted by 1, and should be regularly assessed by a healthcare provider to determine the stage of labor and identify any potential complications.
- The deceleration phase, which is often misunderstood, is a critical component of labor evaluation, and its proper assessment is essential to identify potential complications, such as cephalopelvic disproportion (CPD) and shoulder dystocia, as noted by 1. Overall, a comprehensive assessment of uterine contractions during labor should include monitoring frequency, duration, and intensity, as well as evaluating the progression of cervical dilation, to ensure the best possible outcomes for both the mother and the baby, as emphasized 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. Accurate control of the rate of infusion flow is essential An infusion pump or other such device and frequent monitoring of strength of contractions and fetal heart rate are necessary for the safe administration of oxytocin for the induction or stimulation of labor.
- To assess for uterine contractions during labor, monitoring of the following parameters is necessary:
- Frequency of contractions
- Duration of contractions
- Force of contractions
- Resting uterine tone
- Fetal heart rate This assessment should be done frequently to ensure safe administration of oxytocin 2.
From the Research
Assessment of Uterine Contractions
To assess uterine contractions during labor, several methods can be used, including:
- Manual palpation
- External tocodynamometry
- Intrauterine pressure monitoring
- Electrical uterine myometrial activity tracing 3
Methods of Uterine Activity Monitoring
The different methods of uterine activity monitoring have their advantages and limitations:
- External tocodynamometry is non-invasive and widely used, but does not provide information on the strength of uterine contractions and can be limited by signal loss with maternal movements 3
- Intrauterine pressure monitoring provides accurate information on the strength of uterine contractions, but is invasive and has limited use due to potential risks and complications 3, 4
- Internal tocography provides objective information on uterine activity and is essential for accurate assessment of the uterine contraction curve 5
- Electrical uterine monitoring is a non-invasive method that does not require ruptured membranes, but its use is limited due to lack of access, high cost, and need for training 3
Importance of Accurate Uterine Activity Monitoring
Accurate uterine activity monitoring is crucial for:
- Detecting abnormal contraction patterns that can lead to adverse fetal outcomes 5, 6
- Maintaining fetal well-being during labor by ensuring a sufficiently long relaxation time between contractions 5, 6
- Preventing fetal acidemia by detecting excessive uterine activity 6
- Guiding the use of uterotonic medications or tocolytic medications in cases of threatened preterm labor or tachysystole 3
Comparison of Uterine Activity Monitoring Methods
Studies have compared the effectiveness of different uterine activity monitoring methods, including: