Editing Cardiotocography (section)

===Saltatory pattern of fetal heart rate===
A saltatory pattern of fetal heart rate is defined in cardiotocography (CTG) guidelines by FIGO as fetal heart rate (FHR) baseline amplitude changes of more than 25 beats per minute (bpm) with a duration of >30 minutes.<ref name=FIGOconsensus>{{Cite journal|last1=Ayres-de-Campos|first1=Diogo|last2=Spong|first2=Catherine Y|last3=Chandraharan|first3=Edwin|date=October 2015|title=FIGO consensus guidelines on intrapartum fetal monitoring: Cardiotocography|journal=[[International Journal of Gynecology & Obstetrics]]|volume=131|issue=1|pages=13–24|doi=10.1016/j.ijgo.2015.06.020|issn=1879-3479|pmid=26433401|doi-access=free|hdl=10067/1401570151162165141|hdl-access=free}}</ref><ref name=NICEguideline>{{Cite web|url=https://www.nice.org.uk/guidance/cg190/resources/interpretation-of-cardiotocograph-traces-pdf-248732173|title=NICE/RCOG CTG Guidelines 2017|website=[[National Institute for Health and Care Excellence]]|date=3 December 2014 |url-status=live|archive-url=https://web.archive.org/web/20200727092726/https://www.nice.org.uk/guidance/cg190/resources/interpretation-of-cardiotocograph-traces-pdf-248732173|archive-date=2020-07-27|format=PDF}}</ref>

In a 1992 study, the saltatory pattern FHR was defined by O'Brien-Abel and Benedetti as "[f]etal heart baseline amplitude changes of greater than 25{{nbsp}}bpm with an oscillatory frequency of greater than 6 per minutes for a minimum duration of 1 minute".<ref>{{Cite journal|last1=O'Brien-Abel|first1=Nancy E.|last2=Benedetti|first2=Thomas J.|date=March 1992|title=Saltatory Fetal Heart Rate Pattern|journal=[[Journal of Perinatology]]|volume=12|issue=1|pages=13–17|issn=0743-8346|pmid=1560284}}</ref> The [[pathophysiology]] of the saltatory pattern is not well-known.<ref name=FIGOconsensus/><ref name=NICEguideline/> It has been linked with rapidly progressing hypoxia,<ref>{{Cite journal|url=http://www.eurekaselect.com/120092/article|title=Saltatory and Sinusoidal Fetal Heart Rate (FHR) Patterns and significance of FHR 'Overshoots'|last1=Yanamandra|first1=Niraj|last2=Chandraharan|first2=Edwin|date=2013-07-31|journal=Current Women's Health Reviews|volume=9|issue=3|pages=175–182|language=en|doi=10.2174/157340480903140131111914|url-access=subscription}}</ref> for example due to an [[umbilical cord]] compression, and it is presumed to be caused by an instability of the fetal [[central nervous system]].<ref name=FIGOconsensus/>

In a study by Nunes et al. (2014),<ref>{{Cite journal|last1=Nunes|first1=I.|last2=Ayres-de-Campos|first2=D.|last3=Kwee|first3=A.|last4=Rosén|first4=K. G.|date=2014|title=Prolonged saltatory fetal heart rate pattern leading to newborn metabolic acidosis|journal=Clinical and Experimental Obstetrics & Gynecology|volume=41|issue=5|pages=507–511|doi=10.12891/ceog17322014 |issn=0390-6663|pmid=25864248|s2cid=42931226 |doi-access=free}}</ref> four saltatory patterns in CTG exceeding 20 minutes in the last 30 minutes before birth were associated with fetal [[metabolic acidosis]]. According to this study, saltatory pattern is a relatively rare condition; only four cases were found from three large databases.

In a study by Tarvonen et al. (2019),<ref name=Tarvonen2019>{{Cite journal|last1=Tarvonen|first1=Mikko|last2=Sainio|first2=Susanna|last3=Hämäläinen|first3=Esa|last4=Hiilesmaa|first4=Vilho|last5=Andersson|first5=Sture|last6=Teramo|first6=Kari|date=2019-12-17|title=Saltatory Pattern of Fetal Heart Rate during Labor Is a Sign of Fetal Hypoxia|journal=Neonatology|volume=117|issue=1|pages=111–117|doi=10.1159/000504941|issn=1661-7819|pmid=31846958|s2cid=209408174}}</ref> it was demonstrated that the occurrence of saltatory pattern (already with the minimum duration of 2 minutes) in CTG tracings during labor was associated with [[fetal hypoxia]] indicated by high [[umbilical vein]] (UV) blood [[erythropoietin]] (EPO) levels and [[umbilical artery]] (UA) blood [[acidosis]] at birth in human fetuses. As saltatory patterns preceded late decelerations of fetal heart rate (FHR) in the majority of cases, saltatory pattern seems to be an early sign of fetal hypoxia.<ref>{{Cite journal|url=https://www.karger.com/Article/FullText/504941|title=Saltatory Pattern of Fetal Heart Rate during Labor Is a Sign of Fetal Hypoxia|first1=Mikko|last1=Tarvonen|first2=Susanna|last2=Sainio|first3=Esa|last3=Hämäläinen|first4=Vilho|last4=Hiilesmaa|first5=Sture|last5=Andersson|first6=Kari|last6=Teramo|date=February 19, 2020|journal=Neonatology|volume=117|issue=1|pages=111–117|via=www.karger.com|doi=10.1159/000504941|pmid=31846958|s2cid=209408174|url-access=subscription}}</ref> According to the authors, awareness on this gives [[obstetrician]]s and [[midwives]] time to intensify electronic fetal monitoring and to plan possible interventions before fetal [[asphyxia]] occurs.<ref name=Tarvonen2019/>

Due to a standardized terminology and to avoid miscommunication on CTG interpretation, it has been recently proposed in an exhaustive BJOG review of animal and human studies that terms such as saltatory pattern, ZigZag pattern and marked variability should be abandoned, and the common term "increased variability" should be used in clinical CTG guidelines.<ref>{{Cite journal |last1=Tarvonen |first1=MJ |last2=Lear |first2=CA |last3=Andersson |first3=S |last4=Gunn |first4=AJ |last5=Teramo |first5=KA |title=Increased variability of fetal heart rate during labour: a review of preclinical and clinical studies |journal=BJOG |year=2022 |volume=2022 |issue=12 |pages=2070–2081 |doi=10.1111/1471-0528.17234 |pmid=35596699 |pmc=9796294 |s2cid=248948040 |doi-access=free }}</ref><ref>{{Cite journal |last=Tarvonen |first=Mikko |date=13 March 2023 |title=Increased variability of fetal heart rate: from evidence to implementation |url=https://obgyn.onlinelibrary.wiley.com/doi/10.1111/1471-0528.17488 |journal=BJOG |volume=2023;00:1–2 |issue=12 |pages=1558–1559 |doi=10.1111/1471-0528.17488 |pmid=37055662 |s2cid=258135555 |via=PubMed|url-access=subscription }}</ref>