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

Abstract

ObjectiveTo evaluate the effect, on birth weight and birth weight centile, of use of the PrenaBelt, a maternal positional therapy device, during sleep in the home setting throughout the third trimester of pregnancy.DesignA double-blind, sham-controlled, randomised clinical trial.SettingConducted from September 2015 to May 2016, at a single, tertiary-level centre in Accra, Ghana.ParticipantsTwo-hundred participants entered the study. One-hundred-eighty-one participants completed the study. Participants were women, 18 to 35 years of age, with low-risk, singleton, pregnancies in their third-trimester, with body mass index <35 kg/m2at the first antenatal appointment for the index pregnancy and without known foetal abnormalities, pregnancy complications or medical conditions complicating sleep.InterventionsParticipants were randomised by computer-generated, one-to-one, simple randomisation to receive either the PrenaBelt or sham-PrenaBelt. Participants were instructed to wear their assigned device to sleep every night for the remainder of their pregnancy (approximately 12 weeks in total) and were provided a sleep diary to track their use. Allocation concealment was by unmarked, security-tinted, sealed envelopes. Participants and the outcomes assessor were blinded to allocation.Primary and secondary outcome measuresThe primary outcomes were birth weight and birth weight centile. Secondary outcomes included adherence to using the assigned device nightly, sleeping position, pregnancy outcomes and feedback from participants and maternity personnel.ResultsOne-hundred-sixty-seven participants were included in the primary analysis. The adherence to using the assigned device nightly was 56%. The mean ±SD birth weight in the PrenaBelt group (n=83) was 3191g±483 and in the sham-PrenaBelt group (n=84) was 3081g±484 (difference 110 g, 95% CI −38 to 258, p=0.14). The median (IQR) customised birth weight centile in the PrenaBelt group was 43% (18 to 67) and in the sham-PrenaBelt group was 31% (14 to 58) (difference 7%, 95% CI −2 to 17, p=0.11).ConclusionsThe PrenaBelt did not have a statistically significant effect on birth weight or birth weight centile in comparison to the sham-PrenaBelt.Trial registration numberNCT02379728.

Maternal positional therapy for fetal growth and customised birth weight centile benefit in a Bayesian reanalysis of a double-blind, sham-controlled, randomised clinical trial

“…Of two-hundred and seventy-six participants assessed for eligibility, 200 were recruited, and 167 (n=83 in the PT group, and n=84 in the sham-PT group) were included in the final analysis of the CBWC. See the original GPT publication for full details on excluded participants and sample characteristics 28…”

“…The sham-PT device was identical in appearance, materials and construction to the PT device, but had soft foam balls instead of firm plastic balls and did not have foam inserts. See the original GPT publication for further details regarding the recruitment and follow-up processes 28…”

“…In the Bayesian framework, we analyse only the CBWC because the CBWC, owing to its incorporation of the six main non-pathological factors impacting birth weight, is a much more accurate proxy for fetal growth in comparison to birth weight. For a full description of how the measurements composing the CBWC were taken in the GPT, including the study personnel responsible for collecting them, see the original publication 28…”

“…In the GPT, all data were double-entered from scanned PDFs into Microsoft Excel and double-entry checked prior to the final analysis 28. These data were provided by the principal investigator of the original study (JC).…”

“…In 2013, the authors (JC, AK and JW) developed and tested a positional therapy (PT) device to minimise time spent sleeping in the supine position in pregnancy 26–28. The device does not prevent the user from lying supine during sleep, but it has been shown to cause a significant reduction in the amount of time spent sleeping supine without demonstrable impact on sleep quantity or quality 26 27.…”