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Fetal Monitoring Strips Case Study

1. Hon EH. The electronic evaluation of the fetal heart rate. Am J Obstet Gynecol. 1958;75:1215....

2. National Center for Health Statistics. Advance report of maternal and infant health data from the birth certificate, 1991. Monthly vital statistics report; vol. 42, no. 11. Hyattsville, Md.: Public Health Service, 1994.

3. Boehm FH, Fields LM, Hutchison JM, Bowen AW, Vaughn WK. The indirectly obtained fetal heart rate: Comparison of first- and second-generation electronic fetal monitors. Am J Obstet Gynecol. 1986;155:10–4.

4. Fetal heart rate patterns: monitoring, interpretation, and management. ACOG technical bulletin no. 207. Washington, D.C.: ACOG, 1995.

5. National Center for Health Statistics. Annual summary of births, marriages, divorces, and deaths: United States, 1993. Monthly vital statistics report; vol. 42, no. 13. Hyattsville, Md.: Public Health Service, 1995.

6. Shields D. Fetal and maternal monitoring: maternal reactions to fetal monitoring. Am J Nurs. 1978;78:2110–2.

7. U.S. Preventive Services Task Force. Guide to clinical preventive services. 2d ed. Baltimore: Williams & Wilkins, 1996:433–42.

8. Vintzileos AM, Nochimson DJ, Guzman ER, Knuppel RA, Lake M, Schifrin BS. Intrapartum electronic fetal heart rate monitoring versus intermittent auscultation: a meta-analysis. Obstet Gynecol. 1995;85:149–55.

9. Sandmire HF. Whither electronic fetal monitoring? Obstet Gynecol. 1990;76:1130–4.

10. Schifrin BS. Medicolegal ramifications of electronic fetal monitoring during labor. Clin Perinatol. 1995;22:837–54.

11. Byrd JE. Intrapartum electronic fetal heart rate monitoring (EFM) and amnioinfusion. Advanced Life Support in Obstetrics Course Syllabus. Kansas City, Mo.: American Academy of Family Physicians, 1996:97–106.

12. Assessment of fetal and newborn acid-base status. ACOG technical bulletin no. 127. Washington, D.C.: ACOG, 1989.

13. Clark SL, Paul RH. Intrapartum fetal surveillance: the role of fetal scalp blood sampling. Am J Obstet Gynecol. 1985;153:717–20.

14. Wolkomir MS. Understanding and interpreting intrapartum fetal heart rate monitoring. Milwaukee: Center for Ambulatory Teaching Excellence, Department of Family and Community Medicine, Medical College of Wisconsin, 1995:1–19.

15. Hutson JM, Mueller-Heubach E. Diagnosis and management of intrapartum reflex fetal heart rate changes. Clin Perinatol. 1982;9:325–37.

16. Gimovsky ML, Caritis SN. Diagnosis and management of hypoxic fetal heart rate patterns. Clin Perinatol. 1982;9:313–24.

17. Kurse J. Electronic fetal monitoring during labor. J Fam Pract. 1982;15:35–42.

18. Druzin ML. Antepartum fetal heart rate monitoring. State of the art. Clin Perinatol. 1989;16:627–42.

19. Martin CB Jr. Physiology and clinical use of fetal heart rate variability. Clin Perinatol. 1982;9:339–52.

20. Beard RW, Filshie GM, Knight CA, Roberts GM. The significance of the changes in the continuous fetal heart rate in the first stage of labour. J Obstet Gynaecol Br Commonw. 1971;78:865–81.

21. Krebs HB, Petres RE, Dunn LJ, Jordaan HV, Segreti A. Intrapartum fetal heart rate monitoring. I. Classification and prognosis of fetal heart rate patterns. Am J Obstet Gynecol. 1979;133:762–72.

22. Paul RH, Suidan AK, Yeh S, Schifrin BS, Hon EH. Clinical fetal monitoring. VII. The evaluation and significance of intrapartum baseline FHR variability. Am J Obstet Gynecol. 1975;123:206–10.

23. Hagay ZJ, Weissman A, Lurie S, Insler V. Reversal of fetal distress following intensive treatment of maternal diabetic ketoacidosis. Am J Perinatol. 1994;11:430–2.

24. Schneider EP, Tropper PJ. The variable deceleration, prolonged deceleration, and sinusoidal fetal heart rate. Clin Obstet Gynecol. 1986;29:64–72.

25. Bissonnette JM. Relationship between continuous fetal heart rate patterns and Apgar score in the newborn. Br J Obstet Gynecol. 1975;82:24–8.

26. Goodlin RC, Lowe EW. A functional umbilical cord occlusion heart rate pattern. The significance of overshoot. Obstet Gynecol. 1974;43:22–30.

History

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:

  • Variability: Minimal

  • Baseline Rate: 150 beats/min

  • Episodic Pattern: None

  • Periodic Pattern: None noted

  • Uterine Contractions: Low-amplitude, frequent contractions

  • Interpretation: Category II: Indeterminate, which means that it is not predictive of abnormal fetal acid-base status

  • Differential Diagnosis: Fetal anemia possibly due to a placental abruption, fetal maternal hemorrhage, ruptured vasa previa, or hemolytic anemia

  • Action: The goal is to optimize blood flow to the uterus and improve oxygenation to the fetus. Potential interventions include maintaining continuous fetal monitoring, placing the mother in a lateral position, administering an intravenous bolus of lactated Ringer solution, and administering 100% oxygen per nonrebreather mask. Even though the baseline rate is within the normal range, the minimal variability and the biophysical score of 2/10 are very concerning. Loss of variability is more predictive of hypoxemia and acidemia in a preterm fetus compared with a term fetus. A preterm fetus also can progress much faster from a reassuring to nonreassuring FHR status than a term fetus (Freeman et al, 2003). A Kleihauer-Betke blood test is ordered to determine if fetal hemoglobin cells are present in the maternal bloodstream.

The noted actions are taken, and an immediate tracing is obtained (Fig. 2).

Findings on EFM Strip #2 are:

  • Variability: Initially moderate, then indeterminant

  • Baseline Rate: Initially 135 beats/min, then unable to determine due to development of a sinusoidal pattern

  • Episodic Pattern: Appears to be a deceleration but due to a 3-minute gap of missing data in the tracing, the type of deceleration cannot be determined

  • Periodic Pattern: None noted

  • Uterine Contractions: Irregular and mild by palpation

  • Interpretation: A sinusoidal pattern would be classified as a Category III FHR tracing, which means that it is predictive of abnormal fetal acid-base status at the time of observation

  • Differential Diagnosis: Fetal anemia of unknown cause. However, the presence of decreased fetal movement in conjunction with a sinusoidal pattern suggests that a fetomaternal hemorrhage may be the cause. In addition to fetal anemia, a true sinusoidal pattern is associated with hypoxia/asphyxia, fetal infection, and fetal cardiac anomalies. Whatever the pathology, a true sinusoidal pattern is a significant finding that implies fetal decompensation and requires immediate intervention.

  • Action: Proceed with plans to deliver the baby. Notify the neonatal intensive care staff and neonatologist of fetal status. Continue with all of the previous interventions.

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:

  • Variability: Minimal

  • Baseline Rate: 145 beats/min

  • Episodic Pattern: None noted

  • Periodic Pattern: None noted

  • Uterine Contractions: Every 2 minutes, lasting 40 to 60 seconds. Intensity and resting tone are obtained per palpation

  • Interpretation: Category II FHR

  • Actions: Despite the disappearance of the sinusoidal pattern and the presence of a normal baseline FHR, the continued minimal variability and concerning findings on diagnostic tests warrant an immediate delivery.

Outcome

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.