Modifying Maternal Sleep Position in Late Pregnancy Through Positional Therapy: A Feasibility Study

Abstract

Study objectives: To test whether a customized positional therapy device, PrenaBelt, would reduce time spent sleeping supine and evaluate any change in maternal or fetal parameters, in a group of healthy pregnant women in the third trimester of pregnancy.

Methods: Participants underwent an in-home, overnight sleep study during late pregnancy (32-38 weeks). Participants were observed over 2 nights: 1 night when the PrenaBelt was not worn (nonintervention or control) and 1 night when it was (intervention). The intervention night was randomly allocated, and the study nights were consecutive. On the control night, participants were filmed using a night-capable (infrared) video camera, maternal sleep was measured by the Watch-PAT200, and the fetus was continuously monitored using the Monica AN24. On the intervention night, video, maternal, and fetal monitoring were repeated with the addition of the mother wearing the PrenaBelt.

Results: A total of 25 healthy pregnant women were studied. Four had missing data for the Watch-PAT or Monica, and eight had missing or disrupted video data. Video-determined time in bed was not significantly different during intervention and control nights (P = .196, r = -.23). Median time spent supine during the intervention night was reduced from 48.3 minutes, to 28.5 minutes during the control night (P = .064, r = -.33). The difference in the proportion of time spent supine was significant (P = .039). There was no significant difference in objectively estimated sleep time (P = .651, r = -.07). Improvement was observed in both maternal and fetal parameters during the intervention night with an increase in median minimum maternal oxygen saturations (control = 91.6%, intervention = 92.4%, P = .006, r = -.42), fewer maternal oxygen desaturations (control = 7.1, intervention = 5.9, P = .095, r = -.26), and fewer fetal heart rate decelerations (control = 14.0, intervention = 10.4, P = .045, r = -.31) compared to the control night.

Conclusions: Results provide preliminary evidence that an intervention to reduce supine sleep in late pregnancy may provide maternal and fetal health benefits, with minimal effect on maternal perception of sleep quality and objectively estimated sleep time. Further research to explore relationships between objectively determined maternal sleep position, maternal respiratory indices, and fetal well-being is warranted.

Keywords: positional therapy; pregnancy; sleep position; stillbirth.

© 2018 American Academy of Sleep Medicine.

Figures

Figure 1. PrenaBelt: a positional therapy device designed specifically for pregnant women.

PrenaBelt (Global Innovations for Reproductive Health & Life, Cleveland, Ohio, USA Patent #WO2016176632A1). Device for investigational use only. BPS = body position sensor.

Figure 2. CONSORT diagram.

There were 25 participants enrolled into this repeated-measures study. Participants were randomized to completed either the intervention or the control night first. Equipment failures for Monica AN24, Watch-PAT, and video recordings are shown, leading to final complete datasets for both intervention and control nights of n = 18 for the primary video analyses, and n = 21 for the primary Monica AN24 and Watch-PAT analyses.

Figure 3. Sleep position for each participant (lines) on control (left) and intervention (right) nights by elapsed time in bed.

n = 16 participants are shown. These participants have complete video records for both nights. The first 5 hours are shown, because these participants were in bed for at least 5 hours on both nights.

Figure 4. Number of participants on their back on control (dotted line) and intervention (solid line) nights by elapsed time in bed.

n = 16 participants are shown. These participants have complete video records for at least 5 hours on both nights.

Figure 5. Maternal AHI, maternal oxygen desaturations, minimum maternal oxygen saturation, and FHR decelerations during the control and intervention nights by SDB group.

n = 21 participants are shown (no SDB = 14, SDB = 7). AHI = apnea-hypopnea index, FHR = fetal heart rate, SDB = sleep-disordered breathing.

Figure 6. Example results from individual number 20 during the control (left) and intervention (right) nights.

Large (>15 bpm, dark red) and small (>10 bpm, light red) FHR decelerations are shown (upper) relative to maternal sleep position (lower). Proportion of sleep time spent on back (red), left (green) and right (black) is shown across clock time. Maternal AHI and desaturation count for each night are also indicated. AHI = apnea-hypopnea index, FHR = fetal heart rate.