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Circadian rhythm of frequency‐domain measures of heart rate variability in pregnancy
Author(s) -
Ekholm Eeva M. K.,
Hartiala Jaakko,
Huikuri Heikki V.
Publication year - 1997
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1997.tb12027.x
Subject(s) - heart rate variability , pregnancy , circadian rhythm , medicine , heart rate , baroreflex , cardiology , ambulatory , electrocardiography , rhythm , obstetrics , blood pressure , biology , genetics
Objective To examine frequency domain measures of heart rate variability and their circadian rhythms in pregnancy. Design A longitudinal study. Setting University hospital in Turku, Finland. Participants Sixteen healthy women between 11 and 27 weeks of pregnancy; 12 women before pregnancy; and four women postpartum. Main outcome measures Heart rate variability as measured in frequency domain from 24‐hour ambulatory electrocardiography. Results Pregnancy was associated with a lower standard deviation of R‐R intervals ( P < 0.01 ), with reduced very low ( P < 0.05 ), low ( P < 0.01 ), and high frequency ( P < 0.05 ) power spectral components of heart rate variability. The high frequency power was lower at night in pregnancy, but similar in the daytime in pregnant and nonpregnant women. Conclusions Pregnancy is associated with an overall reduction in heart rate variability, most markedly reflected in the low frequency component. This suggests altered baroreflex or sympathetic modulation of heart rate, and decreased vagal activation at night.