Effect of maternal position and uterine activity on periodic maternal heart rate changes before elective cesarean section at term

Abstract

In a subgroup of pregnant women at term, uterine activity was associated with periodic decelerations of the MHR. In low risk pregnancies there seems to be no effect on the FHR pattern. Implications for the compromised fetus have not yet been investigated.

Effects of maternal sleep position on fetal and maternal heart rate patterns using overnight home fetal ECG recordings

“…23 It is likely that FHR patterns are more dominated by rest-activity cycles (60-90 minutes) rather than ultradian and diurnal rhythms observed in adults, that may emerge around 4 months of age. 24 No effect of maternal position on FHR was reported in a study by Ibrahim et al 21 as well as in the home. 25 These investigators reported that, compared with the left side, FHR during supine position was slightly increased, and that both right and supine were associated with reduced SDNN, whereas only supine was associated with decreased RMSSD.…”

Exercise and pregnancy in recreational and elite athletes: 2016 evidence summary from the IOC expert group meeting, Lausanne. Part 1—exercise in women planning pregnancy and those who are pregnant

“…Supine posture leads to compression of the inferior vena cava by the pregnant uterus, which, in turn, decreases stroke volume, end-diastolic volume index and left ventricular ejection time, with decelerations in maternal HR 70. Being motionless (including standing and certain yoga positions) or exercising in the supine position, may decrease venous return and cause hypotension in 10–20% of pregnant women 70–72.…”

Effects of low maternal heart rate on fetal growth and birthweight

“…Other conditions that might be associated with changes in MHR are the position during recording and uterine activity. In a prospective observational study of the effect of position and uterine activity before elective cesarean section, Ibrahim et al . observed periodic changes in MHR for 13 (10.9%) women.…”

“…After having a light snack, they were positioned in a 15° right or left lateral position, with a wedge placed under one of the buttocks to prevent supine hypotension. Detail on the placement of the electrodes on the abdominal wall has been described previously . The five electrodes were then connected to the fetal ECG monitor (AN24, Monica Health Care, Nottingham, United Kingdom).…”

“…One study observed periodic changes in MHR in 10.9% of term pregnancies before elective cesarean section. However, most of the changes (84.6%) were associated with uterine activity …”