Katharina da Silva Lopes, Yo Takemoto, Erika Ota, Shinji Tanigaki, Rintaro Mori

Strict or partial bed rest in hospital or at home is commonly recommended for women with multiple pregnancy to improve pregnancy outcomes. In order to advise women to rest in bed for any length of time, a policy for clinical practice needs to be supported by reliable evidence and weighed against possible adverse effects resulting from prolonged activity restriction. The objective of this review is to assess the effectiveness of bed rest in hospital or at home to improve perinatal outcomes in women with a multiple pregnancy. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 May 2016), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (30 May 2016) and reference lists of retrieved studies. We selected all individual and cluster-randomised controlled trials evaluating the effect of strict or partial bed rest at home or in hospital compared with no activity restriction during multiple pregnancy. Two review authors independently assessed trials for inclusion, extracted data and methodological quality. We evaluated the quality of the evidence using the GRADE approach and summarised it in 'Summary of findings' tables. We included six trials, involving a total of 636 women with a twin or triplet pregnancy (total of 1298 babies). We assessed all of the included trials as having a low risk of bias for random sequence generation. Apart from one trial with an unclear risk of bias, we judged all remaining trials to be of low risk of bias for allocation concealment.Five trials (495 women and 1016 babies) compared strict bed rest in hospital with no activity restriction at home. There was no difference in the risk of very preterm birth (risk ratio (RR) 1.02, 95% confidence interval (CI) 0.66 to 1.58, five trials, 495 women, assuming complete correlation between twins/triplets, low-quality evidence), perinatal mortality (RR 0.65, 95% CI 0.35 to 1.21, five trials, 1016 neonates, assuming independence between twins/triplets, low-quality evidence) and low birthweight (RR 0.95, 95% CI 0.75 to 1.21, three trials, 502 neonates, assuming independence between twins/triplets, low-quality evidence). We observed no differences for the risk of small-for-gestational age (SGA) (RR 0.75, 95% CI 0.56 to 1.01, two trials, 293 women, assuming independence between twins/triplets, low-quality evidence) and prelabour preterm rupture of the membrane (PPROM) (RR 1.30, 95% CI 0.71 to 2.38, three trials, 276 women, low-quality evidence). However, strict bed rest in hospital was associated with increased spontaneous onset of labour (RR 1.05, 95% CI 1.02 to 1.09, P = 0.004, four trials, 488 women) and a higher mean birthweight (mean difference (MD) 136.99 g, 95% CI 39.92 to 234.06, P = 0.006, three trials, 314 women) compared with no activity restriction at home.Only one trial (141 women and 282 babies) compared partial bed rest in hospital with no activity restriction at home. There was no evidence of a difference in the incidence of very preterm birth (RR 2.30, 95% CI 0.84 to 6.27, 141 women, assuming complete correlation between twins, low-quality evidence) and perinatal mortality (RR 4.17, 95% CI 0.90 to 19.31, 282 neonates, assuming complete independence twins, low-quality evidence) between the intervention and control group. Low birthweight was not reported in this trial. We found no differences in the risk of PPROM and SGA between women receiving partial bed rest and the control group (low-quality evidence). Women on partial bed rest in hospital were less likely to develop gestational hypertension compared with women without activity restriction at home (RR 0.30, 95% CI 0.16 to 0.59, P = 0.0004, 141 women).Strict or partial bed rest in hospital was found to have no impact on other secondary outcomes. None of the trials reported on costs of the intervention or adverse effects such as the development of venous thromboembolism or psychosocial effects. The evidence to date is insufficient to inform a policy of routine bed rest in hospital or at home for women with a multiple pregnancy. There is a need for large-scale, multicenter randomised controlled trials to evaluate the benefits, adverse effects and costs of bed rest before definitive conclusions can be drawn.