The effect of heart rate variability on request for labour epidural analgesia.

Maternal heart rate variability of 62 parturients were compared based on their choice of using (epidural group, 44 women) or not using (control, 18 women) epidural analgesia. Baseline heart rate variability and visual analogue scores were recorded when the cervix of the parturient dilated to 2-4 cm, and paired data were collected 1 h later. We found that parturients in the epidural group had greater heart rate variability at the beginning of labour. Multiple logistic regression analysis identified percentage of absolute difference in successive RR intervals exceeding 20 ms as the best indicator of choosing epidural analgesia. Almost all heart rate variability measures were unchanged 1 h later in both groups. We concluded that parturients who chose epidural analgesia had greater heart rate variability, and that percentage of absolute difference in successive RR intervals exceeding 20 ms could reflect their likelihood of requesting epidural analgesia at the beginning of labour.