Strip of the Month

Abstract

Electronic fetal monitoring (EFM) is a popular technology used to establish fetal well-being. Despite its widespread use, terminology used to describe patterns seen on the monitor has not been consistent until recently. In 1997, the National Institute of Child Health and Human Development (NICHD) Research Planning Workshop published guidelines for interpretation of fetal tracings. This publication was the culmination of 2 years of work by a panel of experts in the field of fetal monitoring and has been endorsed by both the American College of Obstetricians and Gynecologists (ACOG) and the Association of Women's Health, Obstetric and Neonatal Nurses (AWHONN). The terminology definitions and assumptions found in the NICHD publication form the basis for interpretation of the fetal tracings in this series and are summarized here. Normal values for arterial umbilical cord gas values and indications of acidosis are defined in the TableT1.Decelerations are tentatively called recurrent if they occur with ≥50% of uterine contractions in a 20-minute period.We encourage readers to examine each strip in the case presentation and make a personal interpretation of the findings before advancing to the expert interpretation provided.A 17-year-old G1P0 is admitted to labor and delivery at term for borderline low amniotic fluid that was discovered at a routine prenatal visit. The patient has a medical history of panic attacks, has no known drug allergies, and reports prenatal vitamins as her only medication during pregnancy. Prenatal laboratory results are within normal limits. Vaginal examination upon admission reveals a cervix dilated 1 cm with an elevated presenting part. A cervical ripening agent followed by oxytocin induction is planned to achieve delivery. A fetal tracing is obtained at the time of insertion of the cervical ripening agent (misoprostol 25 mcg) per vagina (Fig. 1).Findings on EFM Strip #1 are: Five hours later, vaginal examination reveals that the cervix is unchanged. A repeat dose of misoprostol is administered and another tracing is obtained (Fig. 2).Findings on EFT Strip #2 are: Six hours after the last dose of misoprostol, oxytocin augmentation is started. See Figure 3 for the tracing at that time.Findings on EFM Strip #3 are: Three hours later, the cervix has dilated to 3 cm and the presenting part is now at a −2 station. The patient continues to receive a low amount of oxytocin as another fetal tracing is obtained (Fig. 4).Findings on EFM Strip #4 are: Two and a half hours later, an epidural is administered for pain management. Forty minutes later, artificial rupture of membranes is attempted, but no fluid is noted. The fetal tracing obtained at that time is shown in Figure 5.Findings on EFM Strip #5 are: One hour later, an amnioinfusion is started and an intrauterine pressure catheter is placed to measure uterine contractions. The cervix is dilated 3 to 4 cm and 80% effaced, with the station of the presenting part unchanged. One hour after initiation of the amnioinfusion, another tracing is obtained (Fig. 6).Findings on EFM Strip #6 are: Forty minutes later, the physician attempts both scalp stimulation and VAS (Fig. 7).Findings on EFM Strip #7 are: The findings are reviewed with the patient and her family, and a joint decision is made for an emergent cesarean delivery. A viable female infant is delivered approximately 15 minutes later with Apgar scores of 4 and 7 at 1 and 5 minutes, respectively. The infant weighs 7 lb 5 oz. Thick meconium is noted. Umbilical cord gases are obtained, and the infant is admitted to the neonatal intensive care unit in stable condition for observationT2.