From the Guidelines
Protracted active labor is most strongly associated with risk factors such as cephalopelvic disproportion, excessive neuraxial block, poor uterine contractility, fetal malpositions, malpresentations, uterine infection, maternal obesity, advanced maternal age, and previous cesarean delivery, as identified in the most recent study by Friedman and Cohen (1). The key risk factors for protracted active labor can be categorized into maternal and fetal factors. Maternal factors include:
- Advanced maternal age (typically over 35 years)
- Maternal obesity
- Previous cesarean delivery
- Inadequate uterine contractions (hypotonic labor) Fetal factors include:
- Macrosomia (estimated fetal weight >4000g)
- Abnormal fetal position (especially occiput posterior or transverse positions)
- Congenital anomalies Other significant risk factors include:
- Epidural analgesia, which can reduce the effectiveness of contractions
- Premature rupture of membranes
- Chorioamnionitis Early identification of these risk factors allows for closer monitoring and timely interventions, which may include oxytocin augmentation, amniotomy if membranes are intact, or consideration of cesarean delivery if progress remains inadequate despite interventions, as recommended by Friedman and Cohen (1) and supported by other studies (1). Understanding these risk factors helps clinicians anticipate potential labor complications and prepare appropriate management strategies. In cases where protracted active labor is diagnosed, a thorough evaluation for underlying causes, such as cephalopelvic disproportion, is crucial to determine the best course of action, as emphasized by Friedman and Cohen (1) and other experts (1). The use of oxytocin augmentation, starting at 1-2 mU/min and increasing by 1-2 mU/min every 30-60 minutes until adequate contractions are achieved, may be considered to enhance uterine contractions and promote progress in cervical dilatation, as suggested by Friedman and Cohen (1) and other studies (1). However, if evidence of cephalopelvic disproportion is found, cesarean delivery is often the safer option to prevent potential harm to the mother and fetus, as recommended by Friedman and Cohen (1) and supported by other experts (1).
From the FDA Drug Label
Except in unusual circumstances, oxytocin should not be administered in the following conditions: prematurity, borderline cephalopelvic disproportion, previous major surgery on the cervix or uterus including Caesarean section, overdistention of the uterus, grand multiparity or invasive cervical carcinoma The key risk factors for protracted active labor are not directly stated in the label, but the following conditions are listed as precautions for oxytocin administration, which may be related to complications in labor:
- Prematurity
- Borderline cephalopelvic disproportion
- Previous major surgery on the cervix or uterus
- Overdistention of the uterus
- Grand multiparity
- Invasive cervical carcinoma 2
From the Research
Key Risk Factors for Protracted Active Labor
The key risk factors for protracted active labor can be identified based on the available evidence.
- Maternal morbidity is higher in women with protracted active phase labor, with an adjusted odds ratio (aOR) of 2.15 (95% CI 1.62-2.86) for very protracted active phase labor compared to normal active phase labor 3.
- Neonatal morbidity is also higher in women with protracted active phase labor, with an aOR of 1.38 (95% CI 0.98-1.96) for very protracted active phase labor compared to normal active phase labor 3.
- Cephalopelvic disproportion, fetal malposition, and maternal obesity are potential causes of labor dystocia, which can lead to protracted active labor 4.
- Uterine preparation for labor, uterine contractility, and cervical preparation for labor are also important factors that can contribute to protracted active labor 4.
- Intrauterine infection and maternal stress may also play a role in the development of labor dystocia and protracted active labor 4.
Pathophysiology of Labor Dystocia
The pathophysiology of labor dystocia is complex and multifactorial, involving various mechanisms that can lead to slow cervical dilation and fetal descent 4.
- A better understanding of the pathophysiologic mechanisms of labor dystocia could lead to new clinical opportunities to increase the rate of normal vaginal delivery, reduce cesarean birth rates, and improve maternal and neonatal health 4.
- Current clinical approaches to preventing and managing labor dystocia may be limited by the variation in pathophysiologic causes, but treatments targeting specific underlying etiologies could be more effective 4.