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 was endorsed in 2005 by both the American College of Obstetricians and Gynecologists (ACOG) and the Association of Women's Health, Obstetric and Neonatal Nurses (AWHONN). In 2008, ACOG, NICHD, and the Society for Maternal-Fetal Medicine reviewed and updated the definitions for fetal heart rate patterns, interpretation, and research recommendations. Following is a summary of the terminology definitions and assumptions found in the 2008 NICHD workshop report. Normal values for arterial umbilical cord gas values and indications of acidosis are defined in Table 1.Decelerations are tentatively called recurrent if they occur with ≥50% of uterine contractions in a 20-minute period.Decelerations occurring with <50% of uterine contractions in a 20-minute segment are intermittent.A three-tier Fetal Heart Rate Interpretation system has been recommended as follows: Data from Macones GA, Hankins GDV, Spong CY, Hauth J, Moore T. The 2008 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring. Obstet Gynecocol. 2008;112:661–666.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 27-year-old G1 P0000 woman presents to her doctor's office at 32–5/7 weeks’ gestation complaining of decreased fetal movement for the past 24 hours. Fetal monitoring in the office reveals a prolonged deceleration followed by an apparent sinusoidal pattern. The patient and her husband are sent immediately to the perinatal diagnostic center for a biophysical profile. The profile score is 2/10, which is associated with fetal compromise. In addition, Doppler studies show an increase in the peak velocity of systolic blood flow in the middle cerebral artery, which is consistent with fetal anemia. The prenatal course was normal up to this point and the past medical history was negative. The woman is transferred to labor and delivery for further evaluation and preparation for a cesarean section. On arrival to labor and delivery, EFM is begun (Fig. 1), and appropriate laboratory tests for surgery are ordered.Findings on EFM Strip #1 are: The noted actions are taken, and an immediate tracing is obtained (Fig. 2).Findings on EFM Strip #2 are: The Kleihauer-Betke test is positive for fetal cells in the maternal bloodstream, which confirms a fetomaternal hemorrhage. Thirty minutes later, another tracing is obtained (Fig. 3).Findings on EFM Strip #3 are: Forty-five minutes later, a pale viable male infant weighing 1,673 g is delivered by cesarean section. Apgar scores are 8 at 1 and 5 minutes. The baby is sent to the neonatal intensive care unit, where neonatal anemia is diagnosed. He ultimately does well. Pathologic examination of the placenta reveals numerous focal infarctions. A specimen for cord gases was drawn but was not sufficient for testing.