Autonomic Nervous Function in Pregnant and Postpartum Women Measured From Fingertip Volume Pulse Waves

To evaluate the autonomic nervous function noninvasively, quickly and simply using fingertip volume pulse waves and examine the characteristics of each pregnancy stage.

The subjects of the present study are pregnant women aged 20 or older who received pregnancy and delivery care at our hospital between April 2021 and October 2023. We conducted a longitudinal comparison of participants, and measurement data was acquired at least four times between the 10th week of gestation and 1 month postpartum, with intervals of 4-8 weeks. We employed Vital Monitor (Fatigue Science Laboratory Co. Ltd., Japan.) to measure fingertip volume pulse waves and analyzed heart rate variability to evaluate autonomic nervous function of normal pregnant women.

We were able to collect and analyze data prospectively and longitudinally for 22 pregnant women. We could evaluate autonomic nerve function by photoplethysmography for 2 min using the Vital Monitor, which is simpler than those reported previously. In this study, LF/HF ratio, which reflects thesympathetic activity, was highest in late pregnancy and decreased after birth (LF/HF: group3 = 2.26, group4 = 0.94), but no significant difference was observed (p = 0.0511) (Figure 3). HF, which reflects the parasympathetic activity, declined from early to late pregnancy and recovered after birth (HF: group1 = 517 ms²/Hz, group3 = 303 ms²/Hz group4 = 566 ms²/Hz; p = 0.006) (Figure 2).

This study is the first to longitudinally analyze the characteristics of each pregnancy period using fingertip volume pulse waves. Autonomic nervous function was assessed noninvasively and simply from fingertip volume pulse waves of pregnant and postpartum women. This has potential for future applications through further development.