title: Altered autonomic nervous system activity in women with unexplained recurrent pregnancy loss.
abstract: OBJECTIVE
  Autonomic nervous system activity was studied to evaluate the physical and mental state of women with unexplained recurrent pregnancy loss (RPL).
  
  
  METHODS
  Heart rate variability (HRV) is a measure of beat-to-beat temporal changes in heart rate and provides indirect insight into autonomic nervous system tone and can be used to assess sympathetic and parasympathetic tone. We studied autonomic nervous system activity by measuring HRV in 100 women with unexplained RPL and 61 healthy female volunteers as controls. The degree of mental distress was assessed using the Kessler 6 (K6) scale.
  
  
  RESULTS
  The K6 score in women with unexplained RPL was significantly higher than in control women. HRV evaluated on standard deviation of the normal-to-normal interval (SDNN) and total power was significantly lower in women with unexplained RPL compared with control women. These indices were further lower in women with unexplained RPL ≥4. On spectral analysis, high-frequency (HF) power, an index of parasympathetic nervous system activity, was significantly lower in women with unexplained RPL compared with control women, but there was no significant difference in the ratio of low-frequency (LF) power to HF power (LF/HF), an index of sympathetic nervous system activity, between the groups.
  
  
  CONCLUSIONS
  The physical and mental state of women with unexplained RPL should be evaluated using HRV to offer mental support. Furthermore, study of HRV may elucidate the risk of cardiovascular diseases and the mechanisms underlying unexplained RPL.
authors.affiliation: Graduate Schools of Health Sciences, Okayama University, Okayama, Japan.|Infertility Specialist Consultation Center, Okayama, Japan.
authors.forename: Kumie
authors.initials: K
authors.lastname: Kataoka
authors.affiliation: Graduate Schools of Health Sciences, Okayama University, Okayama, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Tomiya
authors.affiliation: Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.|Department of Obstetrics and Gynecology, Okayama University Hospital, Okayama, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Sakamoto
authors.affiliation: Department of Obstetrics and Gynecology, Okayama University Hospital, Okayama, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kamada
authors.affiliation: Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.|Department of Obstetrics and Gynecology, Okayama University Hospital, Okayama, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hiramatsu
authors.affiliation: Graduate Schools of Health Sciences, Okayama University, Okayama, Japan.|Infertility Specialist Consultation Center, Okayama, Japan.|Department of Obstetrics and Gynecology, Okayama University Hospital, Okayama, Japan.
authors.forename: Mikiya
authors.initials: M
authors.lastname: Nakatsuka
mesh_terms: D000026:Abortion, Habitual / Q000503:physiopathology* / Q000523:psychology; D000328:Adult; D001007:Anxiety / Q000453:epidemiology / Q000209:etiology; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001342:Autonomic Nervous System Diseases / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D015415:Biomarkers; D003863:Depression / Q000453:epidemiology / Q000209:etiology; D020964:Embryo Loss / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006339:Heart Rate; D006785:Hospitals, University; D006801:Humans; D007564:Japan / Q000453:epidemiology; D012008:Recurrence; D012307:Risk Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: anxiety; autonomic nervous system; depression; heart rate variability; recurrent pregnancy loss