Modifying maternal sleep position in the third trimester of pregnancy with positional therapy: a randomised pilot trial

Abstract

ObjectiveTo evaluate whether the percentage of time spent supine during sleep in the third trimester of pregnancy could be reduced using a positional therapy device (PrenaBelt) compared with a sham device.DesignA double-blind, randomised, sham-controlled, cross-over pilot trial.SettingConducted between March 2016 and January 2017, at a single, tertiary-level centre in Canada.Participants23 participants entered the study. 20 participants completed the study. Participants were low-risk, singleton, third-trimester pregnant women aged 18 years and older with body mass index <35 kg/m2 at the first antenatal appointment for the index pregnancy and without known fetal abnormalities, pregnancy complications or medical conditions complicating sleep.InterventionsA two-night, polysomnography study in a sleep laboratory. Participants were randomised by computer-generated, one-to-one, simple randomisation to receive either a PrenaBelt or a sham-PrenaBelt on the first night and were crossed over to the alternate device on the second night. Allocation concealment was by unmarked, security-tinted, sealed envelopes. Participants, the recruiter and personnel involved in setting up, conducting, scoring and interpreting the polysomnogram were blinded to allocation.Primary and secondary outcome measuresThe primary outcome was the percentage of time spent supine during sleep. Secondary outcomes included maternal sleep architecture, respiration, self-reported sleep position and feedback.ResultsThe median percentage of sleep time supine was reduced from 16.4% on the sham night to 3.5% on the PrenaBelt night (pseudomedian=5.8, p=0.03). We were unable to demonstrate differences in sleep architecture or respiration. Participants underestimated the time they spent sleeping supine by 7.0%, and six (30%) participants indicated they would make changes to the PrenaBelt. There were no harms in this study.ConclusionsThis study demonstrates that the percentage of sleep time supine during late pregnancy can be significantly reduced via positional therapy.Trial registration numberNCT02377817; Results.

The Ghana PrenaBelt trial: a double-blind, sham-controlled, randomised clinical trial to evaluate the effect of maternal positional therapy during third-trimester sleep on birth weight

“…We did not include objective measures of sleep architecture, timing or duration via actigraphy or polysomnography; thus, we could not confirm sleep duration. However, in two previous studies of the PrenaBelt, the authors were unable to demonstrate an effect on sleep architecture or respiration using actigraphy9 and polysomnography 10…”

“…However, maternity care providers may need to recommend interventions to minimise unintentional supine sleep because, at baseline, most pregnant women continue to spend a significant amount of time sleeping supine in late pregnancy 9 11–13. Providers should be aware that pregnant women underestimate the time they spend sleeping supine 10. Further, a threshold for the proportion of supine sleep that is ‘acceptable’ is unknown.…”

Pool walking may temporarily improve renal function by suppressing renin-angiotensin-aldosterone system in pregnant women

“…On land, the enlarged pregnant uterus might compress the inferior vena cava and abdominal veins through the force of gravity, leading to decreased cardiac preload/output. 25,26 By contrast, buoyancy in water might release the gravity-induced compression and improve cardiac preload/output. 17 Conventional physical activities such as land walking might have some benefits, 1,6,10 whereas exercise on land may have potential risks to reduce renal perfusion and urinary volume through vasoconstriction.…”

Women’s sleep position during pregnancy in low- and middle-income countries: a systematic review

“…The association of maternal supine sleep position with an increased risk of stillbirth is biologically plausible. As pregnancy progresses there is increased aortic and inferior vena caval compression by the gravid uterus [ 4 ]. In the supine position this compression is exacerbated and can result in up to an 85% decrease in blood flow through the woman’s inferior vena cava and up to a 30% decrease through the aorta [ 5 – 7 ].…”