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

OBJECTIVE: To 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.
DESIGN: A double-blind, randomized, sham-controlled, crossover pilot trial.
SETTING: Conducted between March 2016 and January 2017, at a single, tertiary-level center in Canada.
PARTICIPANTS: Twenty-three participants entered the study. Twenty participants completed the study. Participants were low-risk, singleton, third-trimester pregnant women aged 18 years and older with BMI <35 at the first antenatal appointment for the index pregnancy and without known fetal abnormalities, pregnancy complications, or medical conditions complicating sleep.
INTERVENTIONS: A two-night, polysomnography study in a sleep laboratory. Participants were randomized by computer-generated, one-to-one, simple randomization to receive either a the PrenaBelt or a sham-PrenaBelt on the 1st night and were crossed over to the alternate device on the 2nd 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 MEASURES: The primary outcome was the percentage of time spent supine during sleep. Secondary outcomes included maternal sleep architecture, respiration, self-reported sleep position, and feedback.
RESULTS: The 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.
CONCLUSIONS: This study demonstrates that the percentage of sleep time supine during late pregnancy can be significantly reduced via positional therapy.
TRIAL REGISTRATION: ClinicalTrials.gov NCT02377817

【研究目的】评估相较于假装置，使用体位治疗装置（positional therapy device）PrenaBelt是否可降低妊娠晚期孕妇睡眠时仰卧位的时长占比。
【试验设计】一项双盲、随机、假对照、交叉设计的预试验。
【研究地点】于2016年3月至2017年1月在加拿大某单一三级医疗中心开展。
【研究对象】共23名孕妇纳入本研究，最终20名完成全部试验流程。纳入对象为年龄≥18岁的低危单胎妊娠晚期孕妇，本次妊娠首次产前检查时体重指数（BMI）<35，无已知胎儿异常、妊娠并发症或可影响睡眠的内科疾病。
【干预措施】在睡眠实验室开展为期两晚的多导睡眠图（polysomnography）检查。通过计算机生成的1:1简单随机分组，受试者第一晚随机使用PrenaBelt或假PrenaBelt，第二晚交叉使用另一装置。分配隐藏采用无标识、防窥密封信封。受试者、招募人员以及负责多导睡眠图搭建、实施、评分和解读的所有人员均对分组情况设盲。
【主要及次要结局指标】主要结局指标为睡眠时仰卧位的时长占比。次要结局指标包括产妇睡眠结构、呼吸参数、自我报告的睡眠姿势及使用反馈。
【研究结果】假装置组睡眠仰卧位时长占比的中位值为16.4%，PrenaBelt组降至3.5%（伪中位数=5.8，P=0.03）。本研究未观察到睡眠结构或呼吸参数存在显著差异。受试者自我报告的仰卧位睡眠时长较实际值低估了7.0%，其中6名（30%）受试者表示会调整PrenaBelt的使用。本研究未发生任何不良事件。
【结论】本研究证实，通过体位治疗可显著降低妊娠晚期孕妇睡眠时的仰卧位时长占比。
【试验注册】ClinicalTrials.gov NCT02377817