Abnormalities of the First and Second Stages of Labor
Section snippets
Diagnosis and terminology
Dystocia (literally: δυς, abnormal or difficult, and τοκος, labor or delivery, in ancient Greek) is characterized by slow progress or (eventual) arrest of labor. When it results in a CD, the diagnosis is usually described as cephalopelvic disproportion (CPD) or failure to progress. Originally, CPD described obstructed labors occurring as a result of pelvic contracture caused by rickets. Fortunately today, true pelvic contracture is rare and CPD is a subjective diagnosis based on a clinical
Abnormalities of the first stage
The first stage of labor begins with the onset of labor and ends at complete cervical dilatation. It is divided into a latent, early phase, followed by an active phase. Abnormalities of the first stage of labor have been reported in 8% to 11% of women in labor [4], [5]. Sheiner et al [6] studied 92,918 term, singleton, vertex pregnancies, and found that independent risk factors for CD for failure to progress were induction, maternal age greater than 35, fetal weight greater than 4 kg,
Defining the beginning of labor
Friedman [4] defined the beginning of the latent phase (the onset of labor) as the time at which the mother recognizes regular contractions. This definition is overly inclusive because pregnant women may perceive painful contractions at any time in pregnancy, especially near term. If a more strict definition of labor, such as painful contractions associated with cervical change (effacement and dilatation), is used, a similar problem is encountered because effacement and dilatation may occur
Active phase disorders
Disorders of the active phase are common and can be seen in up to 25% of nulliparous labors and in 15% of labors in multiparas [25]. Progress of active labor is usually assessed with vaginal examinations every 2 to 3 hours (try to keep to less than seven to eight examinations total). Given the high interobserver variability of digital cervical examinations, cervical examination by vaginal ultrasound has been advocated for assessment of the adequacy of labor. One study has demonstrated that the
Disorders of the active phase
The disorders of the active phase have been divided into a number of overlapping categories by various investigators. The three major categories are:
- 1.
Protracted or prolonged active phase, also called primary dysfunctional labor
- 2.
Arrest of dilatation or descent, also called secondary arrest
- 3.
Combined disorder
A protracted active phase means that, after entering what should be the active phase (3–4 cm), the rate of cervical dilatation is slow. This is defined statistically as less than the fifth
Management of active phase disorders
Box 2 presents a summary of management of active phase disorders.
Intrapartum strategies to reduce the risk of dystocia
A number of additional, general labor strategies have been studied in an effort to reduce the risk of dystocia (Box 3). These include ambulation, maternal position in labor, continuous support, hydration, and judicious anesthesia.
Second stage of labor (arrest of descent)
Descent and rotation are the primary labor processes in the second stage (Box 4). A large study by Fraser et al found that risk factors for a “difficult delivery” in nulliparas in the second stage of labor were abnormal fetal position; high fetal station at full dilatation (above −2 station); advanced maternal age (>35 years); and maternal height less than 160 cm [47], [47a]. Epidural use was also associated with a difficult delivery, but only if it was placed before 3 cm or after 5 cm. If the
Summary
Abnormalities of the first and second stage of labor are common. Aside from the recommendations of Rouse et al to allow longer oxytocin augmentation in the active phase, there are currently no evidence-based, uniform definitions or guidelines for the management of abnormal labor [21], [38], [40], [41], [53]. Based on the work of various investigators and the authors' own experience, this article summarizes the important considerations and management options for the various phases of labor. The
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Section V. Abnormal labor
Labor: clinical evaluation and management
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Cited by (20)
Effect of hyoscine butyl-bromide on the duration of active phase of labor: A randomized-controlled trial
2017, Taiwanese Journal of Obstetrics and GynecologyCitation Excerpt :In un-augmented labor, HBB did not produce any significant difference in the duration of labor when compared to placebo, among both multipara and primigravidae in the present study. These observations may be due to the fact that slow progress of labor among primigravidae is mostly due to uterine inertia [20] and oxytocin-augmentation would invariably correct this dystocia in most primigravid parturient. It is also well established that HBB has no effect on uterine contractions; its actions in labor are mainly on the cervix, as an antispasmodic agent [4].
Exercise during pregnancy and risk of cesarean delivery in nulliparous women: a large population-based cohort study
2016, American Journal of Obstetrics and GynecologyCitation Excerpt :The most common indication for CD in nulliparous women is dystocia, which includes problems of uterine dysfunction, impaired cervical dilation, and/or fetal descent in the maternal pelvis.34 Dystocia is generally thought to be due to insufficient uterine contractions.35 Recently, athletics and heavy gardening have been found to be protective of dystocia in nulliparous women.36
What is normal progress in the first stage of labour? A vignette study of similarities and differences between midwives and obstetricians
2016, MidwiferyCitation Excerpt :While primary-care midwives are the initiators of a referral due to a prolonged first stage of labour, the expectations and actions of all the different care professionals need to be well attuned. Guidelines on a prolonged first stage of labour are readily available (Ness et al., 2005; NICE - National Institute for Health and Care Excellence, 2014). However, it is unclear what information different obstetrical professionals use to assess a prolonged first stage of labour and to decide when to refer to a clinical setting.
Proposed biological linkages between obesity, stress, and inefficient uterine contractility during labor in humans
2011, Medical HypothesesCitation Excerpt :Dystocia, a general term indicating difficult labor, includes the related labor problems of uterine dysfunction, and impaired cervical dilatation and/or delayed fetal descent in the maternal pelvis. For reasons that remain obscure, nulliparous women are particularly vulnerable to a diagnosis of dystocia during labor with inadequate uterine activity (i.e., uterine dysfunction) cited as the most common cause of dystocia in these women [5]. The occurrence of dystocia in the United States is apparently increasing, as reflected in the rising cesarean section rate among healthy nulliparous women at term with a single fetus in a head down position.
Detection of cephalopelvic disproportion using a virtual reality model: A feasibility study of three cases
2011, Journal de RadiologieEvidence-based labor and delivery management
2008, American Journal of Obstetrics and Gynecology