PMID- 35307959 OWN - NLM STAT- MEDLINE DCOM- 20220413 LR - 20221005 IS - 2051-817X (Electronic) IS - 2051-817X (Linking) VI - 10 IP - 6 DP - 2022 Mar TI - Fetal respiratory movements improve reliability of heart rate variability and suggest a coupling between fetal respiratory arrhythmia and vagal activity. PG - e15224 LID - 10.14814/phy2.15224 [doi] LID - e15224 AB - Fetal heart rate variability (FHRV) reflects autonomic cardiac regulation. The autonomic nervous system constantly adjusts the heart rate to maintain homeostasis. By providing insight into the fetal autonomic state, FHRV has the potential to become an investigational and clinical instrument. However, the method needs standardization and the influence of fetal movements, including fetal respiratory movements, is not well explored. Therefore, in a highly standardized setting, the aim was to evaluate the association between fetal movements and fetal heart rate variability (FHRV) including their impact on reliability. Fetal heart rate was obtained by noninvasive fetal electrocardiography (NI-FECG) and fetal movements by simultaneous ultrasound scanning in 30 healthy singleton pregnant women on two occasions with a maximum interval of 7 days. The standard deviation of normal-to-normal RR-intervals (SDNN), root mean square of successive RR-interval differences (RMDDS), high-frequency power (HF-power), low-frequency power (LF-power), and LF/HF were measured. A multivariate mixed model was used and reliability was defined as acceptable by a coefficient of variance (CV) /=0.80. During time periods with fetal respiratory movements, the highest reliability was achieved. Intra- and inter-observer reliability measurements were very high (CV: 0-9%; ICC >== 0.86). Within the same recording, SDNN and RMSSD achieved acceptable reliability (CV: 14-15%; ICC >== 0.80). However, day-to-day reliability displayed high CV's. In time periods with fetal respiratory movements, as compared to periods with quiescence RMSSD and HF-power were higher (Ratio: 1.33-2.03) and LF/HF power lower (Ratio: 0.54). In periods with fetal body movements SDNN, RMSSD and HF-power were higher (Ratio: 1.27-1.65). In conclusion, time periods with fetal respiratory movements were associated with high reliability of FHRV analyses and the highest values of parameters supposed to represent vagal activity. CI - (c) 2022 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society. FAU - Rahbek Zizzo, Anne AU - Rahbek Zizzo A AUID- ORCID: 0000-0003-0342-0708 AD - Department of Obstetrics and Gynaecology, Aarhus University Hospital, Aarhus N, Denmark. FAU - Kirkegaard, Ida AU - Kirkegaard I AD - Department of Obstetrics and Gynaecology, Aarhus University Hospital, Aarhus N, Denmark. FAU - From Reese, Camille AU - From Reese C AD - Department of Obstetrics and Gynaecology, Aarhus University Hospital, Aarhus N, Denmark. FAU - Hansen, John AU - Hansen J AD - Department of Health Science and Technology, Aalborg University, Aalborg, Denmark. FAU - Uldbjerg, Niels AU - Uldbjerg N AD - Department of Obstetrics and Gynaecology, Aarhus University Hospital, Aarhus N, Denmark. FAU - Molgaard, Henning AU - Molgaard H AD - Department of Cardiology, Aarhus University Hospital, Aarhus N, Denmark. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - United States TA - Physiol Rep JT - Physiological reports JID - 101607800 SB - IM MH - Arrhythmias, Cardiac MH - *Autonomic Nervous System MH - Female MH - *Fetal Movement MH - Heart Rate/physiology MH - Heart Rate, Fetal/physiology MH - Humans MH - Pregnancy MH - Reproducibility of Results PMC - PMC8935276 OTO - NOTNLM OT - autonomic nervous system OT - fetal heart rate variability OT - fetus OT - gestational age OT - reliability OT - respiratory sinus arrhythmia OT - spectral domain OT - time domain OT - vagal activity COIS- No conflicts of interest. EDAT- 2022/03/22 06:00 MHDA- 2022/04/14 06:00 PMCR- 2022/03/21 CRDT- 2022/03/21 05:47 PHST- 2022/02/18 00:00 [received] PHST- 2022/02/21 00:00 [accepted] PHST- 2022/03/21 05:47 [entrez] PHST- 2022/03/22 06:00 [pubmed] PHST- 2022/04/14 06:00 [medline] PHST- 2022/03/21 00:00 [pmc-release] AID - PHY215224 [pii] AID - 10.14814/phy2.15224 [doi] PST - ppublish SO - Physiol Rep. 2022 Mar;10(6):e15224. doi: 10.14814/phy2.15224.