A 23-year-old woman, gravida 1 para 0, at 41 weeks gestation is admitted to labor and delivery for contractions over the past 3 hours. The patient has no chronic medical conditions. She had an elevated 1-hour glucose challenge test but normal 3-hour glucose tolerance test at 28 weeks gestation. The patient receives epidural analgesia immediately upon admission and has spontaneous rupture of membranes 2 hours after admission. An intrauterine pressure catheter is placed for variable decelerations, which resolve with an amnioinfusion. Her cervical examinations are shown below: Current temperature is 36.7 C (98 F). Fetal heart rate tracing shows a baseline of 140/min, moderate variability, and multiple accelerations. Intrauterine pressure catheter shows an average of 200 Montevideo units every 10 minutes for the last 4 hours. Which of the following is the best next step in management of this patient?

Question

A 23-year-old woman, gravida 1 para 0, at 41 weeks gestation is admitted to labor and delivery for contractions over the past 3 hours.  The patient has no chronic medical conditions.  She had an elevated 1-hour glucose challenge test but normal 3-hour glucose tolerance test at 28 weeks gestation.  The patient receives epidural analgesia immediately upon admission and has spontaneous rupture of membranes 2 hours after admission.  An intrauterine pressure catheter is placed for variable decelerations, which resolve with an amnioinfusion.  Her cervical examinations are shown below:  Current temperature is 36.7 C (98 F).  Fetal heart rate tracing shows a baseline of 140/min, moderate variability, and multiple accelerations.  Intrauterine pressure catheter shows an average of 200 Montevideo units every 10 minutes for the last 4 hours.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_da46_7445_bc81_dd2067585cfa_MD0003_00 The active phase of labor (6-10 cm cervical dilation) has an expected, predictable rate of cervical dilation of ≥1 cm every 2 hours. This patient's labor curve shows she dilated from 5 cm to 7 cm in the first 2 hours, crossing from the latent phase into the active phase. Once in the active phase, she dilated from 7 cm to 8 cm in 2 hours (ie, an appropriate rate of dilation of 1 cm/2 hrs). However, for the past 4 hours her cervix has been unchanged (8 cm) despite adequate contractions (ie, ≥200 Montevideo units averaged over 10 minutes), which is consistent with active phase arrest. Active phase arrest is also defined as no cervical change in ≥6 hours with inadequate contractions. This patient's active phase arrest is likely due to her late-term gestation (≥41 weeks) and possible fetal macrosomia (eg, abnormal 1-hour glucose challenge test), which contribute to cephalopelvic disproportion, a common cause of labor arrest. In patients with active phase arrest, the best next step in management is cesarean delivery because no further cervical dilation is expected and continuing current management increases maternal-fetal morbidity (eg, intra-amniotic infection, fetal hypoxemia) (Choice B). (Choice A) Prostaglandin is used for cervical ripening (softening and thinning of the cervix) in early labor induction. It is not used to augment active labor. (Choice C) An operative vaginal delivery (eg, vacuum-assisted vaginal delivery) is performed during the second stage of labor (10 cm dilation until fetal delivery) to expedite delivery for category III tracings or maternal exhaustion. This patient is 8 cm dilated. (Choice D) A fetal scalp electrode is an internal device placed after rupture of membranes when external monitoring cannot reliably measure fetal heart rate (eg, maternal obesity). The fetal heart rate tracing is category I (normal). (Choice F) Oxytocin is a uterotonic used to augment labor (by increasing the frequency and force of contractions) if contractions are inadequate (<200 Montevideo units). Oxytocin augmentation is used in protracted labor (ie, cervical dilation rate <1 cm/2 hours but not arrested). Educational objective: Active phase arrest is no cervical change in ≥4 hours with adequate contractions (≥200 Montevideo units averaged over 10 minutes), or no change in ≥6 hours with inadequate contractions. Labor arrest is managed by cesarean delivery. References: Contemporary patterns of spontaneous labor with normal neonatal outcomes. (http://www.ncbi.nlm.nih.gov/pubmed/21099592) Preventing the first cesarean delivery: summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, and American College of Obstetricians and Gynecologists Workshop. (http://www.ncbi.nlm.nih.gov/pubmed/23090537)

A 23-Year-Old Woman, Gravida 1 Para 0, at 41 Weeks