What is the "normal" fetal heart rate?

Stephanie Pildner von Steinburg, Anne-Laure Boulesteix, Christian Lederer, Stefani Grunow, Sven Schiermeier, Wolfgang Hatzmann, Karl-Theodor M Schneider, Martin Daumer, Stephanie Pildner von Steinburg, Anne-Laure Boulesteix, Christian Lederer, Stefani Grunow, Sven Schiermeier, Wolfgang Hatzmann, Karl-Theodor M Schneider, Martin Daumer

Abstract

Aim. There is no consensus about the normal fetal heart rate. Current international guidelines recommend for the normal fetal heart rate (FHR) baseline different ranges of 110 to 150 beats per minute (bpm) or 110 to 160 bpm. We started with a precise definition of "normality" and performed a retrospective computerized analysis of electronically recorded FHR tracings. Methods. We analyzed all recorded cardiotocography tracings of singleton pregnancies in three German medical centers from 2000 to 2007 and identified 78,852 tracings of sufficient quality. For each tracing, the baseline FHR was extracted by eliminating accelerations/decelerations and averaging based on the "delayed moving windows" algorithm. After analyzing 40% of the dataset as "training set" from one hospital generating a hypothetical normal baseline range, evaluation of external validity on the other 60% of the data was performed using data from later years in the same hospital and externally using data from the two other hospitals. Results. Based on the training data set, the "best" FHR range was 115 or 120 to 160 bpm. Validation in all three data sets identified 120 to 160 bpm as the correct symmetric "normal range". FHR decreases slightly during gestation. Conclusions. Normal ranges for FHR are 120 to 160 bpm. Many international guidelines define ranges of 110 to 160 bpm which seem to be safe in daily practice. However, further studies should confirm that such asymmetric alarm limits are safe, with a particular focus on the lower bound, and should give insights about how to show and further improve the usefulness of the widely used practice of CTG monitoring.

Keywords: Baseline; Cardiotocography; Computerized analysis; Fetal heart rate; Guidelines; Monitoring.

Figures

Figure 1. Histogram of baseline fetal heart…
Figure 1. Histogram of baseline fetal heart rate values
(A) Training data. (B) Validation data. (C) All data. Red bars comprise 25th to 75th percentile, red and green ones 12.5th to 87.5th percentile, red, green and yellow bars 5th to 95th percentile and all bars except white ones comprise 2.5th to 97.5th percentile.
Figure 2. Quantile bands of FHR plotted…
Figure 2. Quantile bands of FHR plotted against gestational age.
FHR (bpm) is plotted against gestational weeks from 20 to 42. Red colours comprise 25th to 75th percentile, red and green colours 12.5th to 87.5th percentile, red, green and yellow colours 5th to 95th percentile and all colours comprise 2.5th to 95.5th percentile.

References

    1. American Congress of Obstetricians and Gynecologists Practice Bulletin No. 109: Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles. Obstetrics and Gynecology. 2009;114:192–202.
    1. Daumer M, Neiss A. A new adaptive algorithm to detect shifts, drifts, and outliers in biomedical time series. In: Kunert J, Trenkler G, editors. Mathematical statistics with applications in biometry. Lohmar: Josef Eul Verlag; 2001.
    1. Daumer M, Scholz M, Boulesteix A-L, Pildner von Steinburg S, Schiermeier S, Hatzmann W, Schneider KTM. The normal fetal heart rate study: analysis plan and amendment. Nature Precedings. 2007 doi: 10.1038/npre.2007.980.1. Available at .
    1. Daumer M, Held U, Ickstadt K, Heinz M, Schach S, Ebers G. Reducing the probability of false positive research findings by pre-publication validation - experience with a large multiple sclerosis database. BMC Medical Research Methodology. 2008;8:18. doi: 10.1186/1471-2288-8-18.
    1. Deutsche Gesellschaft für Gynäkologie und Geburtshilfe Anwendung des CTG während Schwangerschaft und Geburt [Application of CTG during pregnancy and delivery] 2010. Available at .
    1. Deutsche Gesellschaft für Gynäkologie und Geburtshilfe Anwendung des CTG während Schwangerschaft und Geburt [Application of CTG during pregnancy and delivery] 2012. Available through .
    1. Diogo Ayres-de-Campos, Joao Bernardes. Twenty five years after the FIGO guidelines for the use of fetal monitoring: time for a simplified approach? International Journal of Gynaecology and Obstetrics. 2010;110:1–6. doi: 10.1016/j.ijgo.2010.03.011.
    1. Downs T, Zlomke E. Fetal heart rate pattern notification guidelines and suggested management algorithm for intrapartum electronic fetal heart rate monitoring. The Permanente Journal. 2007;11:22–28.
    1. Grivell RM, Alfirevic Z, Gyte GML, Devane D. Antenatal cardiotocography for fetal assessment. Cochrane Database of Systematic Reviews. 2012;(12) doi: 10.1002/14651858.CD007863.pub3. Art. No.: CD007863.
    1. Ioannidis J. Why most published research findings are false. PLoS Medicine. 2005;2(8):e124. doi: 10.1371/journal.pmed.0020124.
    1. Karolina A, Edwin C. Use of continuous electronic fetal monitoring in a preterm fetus: clinical dilemmas and recommendations for practice. Journal of Pregnancy. 2011;2011 doi: 10.1155/2011/848794. Article ID 848794.
    1. König I, Malley JD, Weimar C, Diener HC, Ziegler A. Practical experiences on the necessity of external validation. Statistics in Medicine. 2007;26:5499–5511. doi: 10.1002/sim.3069.
    1. Macones GA, Hankins GD, Spong CY, Hauth J, Moore T. The 2008 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring: update on definitions, interpretation, and research guidelines. Journal of Obstetric, Gynecologic, and Neonatal Nursing. 2008;37:510–515. doi: 10.1111/j.1552-6909.2008.00284.x.
    1. Manassiew N. What is the normal heart rate of a term fetus? British Journal of Obstetrics and Gynaecology. 1996;103:1269–1273.
    1. Manassiev N, Abusheika N, Victor-Olagundoye V, Johnstone M. What is the normal heart rate of a term fetus? Journal of Obstetrics and Gynaecology. 1998;18:442–444. doi: 10.1080/01443619866750.
    1. Murray ML. Maternal or fetal heart rate? Avoiding intrapartum misidentification. Journal of Obstetric, Gynecologic, and Neonatal Nursing. 2004;33:93–104. doi: 10.1177/0884217503261161.
    1. National Institute of Child Health and Human Development Research Planning Workshop Electronic fetal heart rate monitoring: research guidelines for interpretation. American Journal of Obstetrics and Gynecology. 1997;177:1385–1390. doi: 10.1016/S0002-9378(97)70079-6.
    1. National Institute for Health and Clinical Excellence (NICE) Clinical Guideline 55: Intrapartum care: care of healthy women and their babies during childbirth. 2007. Corrected 2008. Available at .
    1. Nijhuis IJM, ten Hof J, Mulder EJH, Nijhuis JG, Narayan H, Taylor DJ, Westers P, Visser GHA. Numerical fetal heart rate analysis – nomograms, minimal duration of recording and intrafetal consistency. Prenatal and Neonatal Medicine. 1998;3:314–322.
    1. Pattison N, McCowan L. The Cochrane Library. Issue 2. Chichester: John Wiley & Sons, Ltd; 2004. Cardiotocography for antepartum fetal assessment (Cochrane Review)
    1. Perinatal Committee of the Japan Society of Obstetrics and Gynecology Guideline for intrapartum management based on FHR interpretation. Acta Obstetrica et Gynaecologica Japonica. 2009;61:1297–1302.
    1. Rooth G, Huch A, Huch R. FIGO news: guidelines for the use of fetal monitoring. International Journal of Gynaecology and Obstetrics. 1987;25:1159–1167.
    1. Royal Australian and New Zealand College of Obstetricians and Gynaecologists . Intrapartum fetal surveillance clinical guidelines. East Melbourne: RANZCOG; 2006.
    1. Saling E. Das Kind im Bereich der Geburtshilfe. Stuttgart: Georg Thieme Verlag; 1966.
    1. Schiermeier S, Pildner von Steinburg S, Thieme A, Reinhard J, Daumer M, Scholz M, Hatzmann W, Schneider KTM. Sensitivity and specificity of intrapartum computerised FIGO criteria for cardiotocography and fetal scalp pH during labour: multicentre, observational study. British Journal of Obstetrics and Gynaecology. 2008;115:1557–1563. doi: 10.1111/j.1471-0528.2008.01857.x.
    1. Schindler T. Delayed moving window algorithm for online cardiotocogram analysis - a comparison of computerized CTG analysis. Aachen: Mainz Verlag; 2002.
    1. Serra V, Bellver J, Moulden M, Redman CWG. Computerized analysis of normal fetal heart rate pattern throughout gestation. Ultrasound in Obstetrics and Gynecology. 2009;34:74–79. doi: 10.1002/uog.6365.
    1. Society of Obstetrics and Gynaecologists of Canada Fetal health surveillance: antepartum and intrapartum consensus guideline. Journal of Obstetrics and Gynaecology Canada. 2007;29:S1–S57.
    1. Vintzileos AM, Nochimson DJ, Guzman ER, Knuppel RA, Lake M, Schifrin BS. Intrapartum electronic fetal heart rate monitoring versus intermittent auscultation: a meta-analysis. Obstetrics and Gynecology. 1995;85:149–155. doi: 10.1016/0029-7844(94)00320-D.

Source: PubMed

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