Management of Prolonged Latent Phase
Labor is divided into three stages. The first stage of labor is divided into two phases – the latent phase and the active phase. In the latent phase, contractions become progressively more coordinated, regular, and frequent, and are associated with cervical change.
The length of the latent phase of labor was informed by the work of Friedman. Friedman defined prolonged latent phase as > 20 hours in a nulliparous woman, and > 14 hours in a multiparous woman using the 95th percentile cutoff. However, Friedman described the active phase as beginning at 4 cm cervical dilatation. More recent data from the Consortium on Safe Labor suggests that the active phase does not start before 6 cm. This would imply that the latent phase length is correspondingly longer than Friedman’s work indicates. However, the definitions of a prolonged latent phase are still based on Friedman data, as modern investigators have not focused attention on the latent phase of labor.
Risk factors for prolonged latent phase include unfavorable cervix, and fetal position of occiput transverse or occiput posterior. Epidural anesthesia does not appear to lengthen the first stage of labor.
Prolonged latent phase labor may result in physical and emotional exhaustion of the mother. Education, support, hydration, position changes, and other non-pharmacologic measures such as massage or water immersion should be first line treatments if maternal and fetal evaluation is reassuring. If these measures do not provide relief, one can consider therapeutic rest or augmentation of labor if the decision to deliver has been made.
Therapeutic rest via analgesics or sedatives, such as morphine (IM or IV), oral narcotics, or short acting benzodiazepines (such as zolpidem) among many others, is appropriate when there is no indication for delivery, to relieve the patient’s discomfort, and to allow rest while monitoring for labor progression. The provider should engage in shared decision making with the patient about continued monitoring in the hospital or possible discharge to home with a plan for communication and subsequent evaluation.
Most women with a prolonged latent phase of labor will enter the active phase with expectant management. The remainder will either stop contracting, or with labor augmentation including amniotomy, oxytocin or both, will achieve the active phase. Expectant management is reasonable for women at 4-6 cm dilation with reassuring maternal and fetal status. A prolonged latent phase is not an indication for cesarean delivery.
Consequences of a prolonged latent phase include increased risk of cesarean delivery. This may be secondary to misdiagnosis of protracted labor and arrest disorders. With prolonged latent phase, there is no increased risk of perinatal mortality. However, there is an increased risk of thick meconium, 5 minutes Apgar score less than 7, and admission to the NICU.
- American College of Obstetricians and Gynecologists; Society for Maternal-Fetal Medicine. Obstetric care consensus no. 1: safe prevention of the primary cesarean delivery. Obstet Gynecol. 2014 Mar;123(3):693-711. doi: 10.1097/01.AOG.0000444441.04111.1d.
- American College of Obstetricians and Gynecologists. Committee on Obstetric Practice. Committee Opinion No. 766: Approaches to Limit Intervention During Labor and Birth. Obstet Gynecol. 2019 Feb;133(2):e164-e173. doi: 10.1097/AOG.0000000000003074.
- Rhoades JS, Cahill AG. Defining and Managing Normal and Abnormal First Stage of Labor. Obstet Gynecol Clin North Am. 2017 Dec;44(4):535-545. doi: 10.1016/j.ogc.2017.07.001.
- Cunningham F, Leveno KJ, Bloom SL, et. al, Abnormal Labor. Williams Obstetrics, 25e New York, NY: McGraw-Hill; 2018. Chapter 23.
Initial Approval: November 2018, Published January 2019; Revised July 2020
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