The heart rate
The FHR rate is calculated outside accelerations and decelerations and actually corresponds to the average of the baseline values.
- the difficulty lies in positioning the baseline (Fig. 1.6); determining it requires a minimum period of 2 minutes;
- this baseline rate is classified as:
- normal, between 110 and 160 bpm; due to vagal dominance, there is a decrease in heart rate during the 3rd trimester; from 36 to 39 weeks, it is < 160 bpm and from 40 to 42 weeks, < 150 bpm.
- tachycardic, if it is above 160 bpm for more than 10 minutes;
- bradycardic, if it is below 110 bpm for more than 10 minutes.
References
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- Ayres-de-Campos D., Spong C. Y., et Chandraharan E. FIGO consensus guidelines on intrapartum fetal monitoring: Cardiotocography. International Journal of Gynecology & Obstetrics, 131 (1): 13–24, 2015b. ISSN 0020-7292. doi: 10.1016/j.ijgo.2015.06.020.
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- Pézard P. et Boussion F. Troubles du rythme cardiaque foetal chap. 9. In Echocardiographie Fœtale, pages 349–359. Elsevier Masson, 2013.
- Sukumaran S., Pereira V., Mallur S., et Chandraharan E. Cardiotocograph (CTG) changes and maternal and neonatal outcomes in chorioamnionitis and/or funisitis confirmed on histopathology. European Journal of Obstetrics & Gynecology and Reproductive Biology, 260: 183–188, 2021.