Abstract Body (Do not enter title and authors here): Maternal mortality is three times higher in Black women compared to non-Hispanic white women. The postpartum period, the time with the least amount of health surveillance, accounts for 65% of maternal deaths. Altered maternal heart rate variability (HRV) may reflect early postpartum cardiovascular complications. Home HRV monitoring could facilitate early detection of postpartum complications and reduce disparities in maternal deaths.

To determine the feasibility of a new method for remotely monitoring HRV in postpartum women. A secondary aim was to explore whether HRV metrics differed between postpartum women with cardiovascular morbidities and those recovering from uncomplicated pregnancies.

Twenty Black postpartum women were instructed to record heart rhythms at home using a wearable sensor for 10 minutes, twice daily, over 4 weeks. Waveforms were uploaded to a cloud server; data were processed to measure HRV metrics (e.g., standard deviation normal sinus beats [SDNN], root mean square of successive differences [RMSSD]), low-frequency (LF, 0.04-0.15 Hz), high-frequency (HF, 0.15-0.4 Hz) oscillations [continuous wavelet transform, 10 sec segments]). To determine whether HRV profiles differ according to risk factors, we compared women who had vaginal births without complications (n = 7) to women with elevated risk factors, such as cesarean birth (n = 7) or preexisting cardiovascular conditions (n = 6). Data were averaged across 4 weeks and reported as mean ± SD.

Data were available from 17 participants—one withdrew and two could not obtain internet access. No serious postpartum complications occurred. Women delivering vaginally (no history of cardiovascular disease) had a mean heart rate of 82.2 ± 6.3 bpm (n = 6), and did not differ significantly (p = 0.23) from the elevated risk group (87.2 ± 8.9 bpm, n = 13). Groups had statistically similar mean values for R-R intervals (183.6 ± 176.6 versus 263.5 ± 201.4 ms), SDNN (392.1 ± 322.1 versus 512.2 ± 327.5 ms), and RMSSD (0.29 ± 0.64 versus 0.49 ± 0.96 ms). Frequency band powers were similar (LF band [0.04 ± 0.05 versus 0.05 ± 0.06 ms2]; HF band [0.04 ± 0.05 versus 0.06 ± 0.07 ms2]), indicating that there was likely no abnormal autonomic modulation of the heart in this sample.

Most participants (85%) completed monitoring, demonstrating the feasibility of our method. Large prospective studies are needed to develop HRV algorithms that could alert postpartum women to seek urgent care for impending complications.