Study characteristics
| Investigator | Country | Participants and methods | Intervention | Outcomes extracted |
|---|---|---|---|---|
| Developing country | ||||
| Crowther et al.,20 1989 | Zimbabwe | 139 women with twin pregnancies at < 34 weeks’ gestation with cervical score ≥ −2 Randomization: block randomization Allocation concealment: consecutively numbered opaque, sealed envelopes Loss to follow-up: 2/70 women in experimental group were noncompliant Exclusion criteria: uncertain gestational age, cervical suture in place, antepartum hemorrhage, hypertension, previous cesarean delivery and in labour Recruitment dates: 1984 onward | Experimental group: in-hospital bed rest Mean gestational age at study start 33.3 (SD 1.8) wk Length: 2.5 wk n = 70 Control group: conventional outpatient management; admitted to hospital if pregnancy complications occurred Mean gestational age at study start 33.5 (SD 1.8) wk Length: 2.3 wk n = 69 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, birth weight < 2500 g, birth weight < 1500 g, SGA, admission to NICU Maternal: cesarean delivery, pregnancy-induced hypertension, PROM |
| Crowther et al.,19 1990 | Zimbabwe | 118 women with uncomplicated twin pregnancies between 28 and 30 weeks’ gestation Randomization: block randomization Allocation concealment: numbered opaque, sealed envelopes Exclusion criteria: cervical suture, hypertension, cesarean delivery scar, antepartum hemorrhage or uncertain gestational age 15/58 in experimental group were noncompliant Recruitment dates: 1984–1986 | Experimental group: in-hospital bed rest; participants were encouraged to rest in bed as much as possible, although voluntary ambulation was allowed Mean gestational age at study start 29.1 (SD 1.2) wk Length: 7.0 wk n = 58 Control group: advised to continue normal activities at home; admitted to hospital if pregnancy complications occurred Mean gestational age at study start 29.2 (SD 1.7) wk Length: 6.7 wk n = 60 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, birth weight < 2500 g, birth weight < 1500 g, SGA, admission to NICU Maternal: cesarean delivery, pregnancy-induced hypertension, PROM |
| Crowther et al.,18 1991 | Zimbabwe | Multiple-gestation births Randomization: block randomization Allocation concealment: opaque, sealed envelopes Loss to follow-up: none | Experimental group: in-hospital bed rest Mean gestational age at study start 29.0 (SD 4.7) wk Length: 5.4 wk n = 10 Control group: advised to continue normal activities at home; admitted to hospital if pregnancy complications occurred Mean gestational age at study start 29.4 (SD 3.0) wk Length: 4.3 wk n = 9 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, birth weight < 2500 g, birth weight < 1500 g, SGA, admission to NICU Maternal: cesarean delivery, pregnancy-induced hypertension, PROM |
| Crowther et al.,22 1992 | Zimbabwe | 218 women with singleton pregnancies at 28–38 weeks’ gestation with nonproteinuric hypertension (blood pressure > 140/90 mm Hg) Randomization: block randomization, stratified Allocation concealment: opaque, sealed envelopes Loss to follow-up: none Recruitment dates: 1985–1986 | Experimental group: admission to hospital for rest Mean gestational age at study start 35.3 (SD 2.6) wk Length: 3.0 wk n = 110 Control group: normal activity at home Mean gestational age at study start 34.6 (SD 3.0) wk Length: 3.6 wk n = 108 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, birth weight < 2500 g, SGA, admission to NICU Maternal: cesarean delivery, preeclampsia |
| Saunders et al.,21 1985 | Zimbabwe | 212 women with twin pregnancies at about 30 weeks’ gestation Randomization: randomized; method not described Allocation concealment: consecutively numbered sealed envelopes Loss to follow-up: 11/105 in experimental group declined hospital admission, and 2/105 delivered before intervention start; 1/107 in control group delivered before intervention start Recruitment dates: not specified | Experimental group: in-hospital bed rest from 32 weeks’ gestation until labour Mean gestational age at study start 32.7 wk Length: 4.6 wk n = 105 Control group: no activity restriction, at home; admitted to hospital if pregnancy complications occurred Gestational age at study start about 32 wk Length: > 5 wk n = 107 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, gestational age, birth weight < 2500 g, birth weight < 1500 g Maternal: preeclampsia |
| Developed countries | ||||
| Bigelow et al.,31 2016 | US | 36 women aged 18–55 yr with singleton pregnancies at < 34 weeks’ gestation with PPROM Randomization: computer-generated randomization scheme Allocation concealment: sealed envelopes Exclusion criteria: actively receiving magnesium sulfate, footling breech presentation, or maternal or fetal indication for immediate delivery Loss to follow-up: 1/18 withdrew from control allocation Recruitment dates: not specified | Experimental group: in-hospital bed rest; instructed to spend majority of day in bed in reclined or sleeping position Mean gestational age at study start 29.2 (SD 5.7) wk Length: 2.7 wk n = 18 Control group: admitted to hospital; asked to walk for minimum of 20 min 3 times daily Mean gestational age at study start 28.9 (SD 7.6) wk Length: 1.6 wk n = 17 Participants in both groups given latency antibiotics ± ampicillin/amoxicillin and erythromycin for up to 7 d and 48-h course of intramuscularly administered betamethasone | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, admission to NICU Maternal: cesarean delivery |
| Dodd et al.,23 2005 | Australia | 7 women with triplet pregnancies Randomization: randomization schedule used variable blocks with stratification by parity Allocation concealment: third party opened consecutively numbered opaque, sealed envelopes and reported allocation over telephone Loss to follow-up: none Recruitment dates: 1996–2003 | Experimental group: in hospital from 24 to 30 weeks’ gestation; biweekly assessment; allowed to leave ward during weekends; encouraged to rest at home following discharge Mean gestational age at study start 23.4 (SD 1.7) wk Length: about 6 wk n = 3 Control group: advised to continue normal activity at home; biweekly in-clinic assessment Mean gestational age at study start 22.0 (SD 1.8) wk Length: about 6 wk n = 4 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, birth weight < 2500 g, birth weight < 1500 g Maternal: cesarean delivery, pregnancy-induced hypertension |
| Elliott et al.,29 2005 | US | 73 women with singleton pregnancies experiencing preterm labour with negative fetal fibronectin recruited from 4 tertiary hospitals in southwestern United States Randomization: computer-generated randomization schedule Allocation concealment: reported to study coordinator by third party, who opened opaque, sealed envelopes Inclusion criteria: > 14 yr of age, intact membranes, documented uterine contractions of > 6/h at admission, 23–33 6/7 weeks’ gestation, < 3 cm cervical dilatation Recruitment dates: November 1997–September 2000 | Experimental group: activity restriction at home; 2 weekly clinic visits, followed by biweekly clinic visits Mean gestational age at study start 30.7 (SD 2.7) wk Length: 5.9 wk n = 36 Control group: instructed to resume normal activities, including work responsibilities, at home; 2 weekly clinic visits followed by biweekly clinic visits Mean gestational age at study start 31.0 (SD 6.3) wk Length: 6.6 wk n = 37 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, birth weight < 2500 g, birth weight < 1500 g, admission to NICU Maternal: none |
| Hartikainen-Sorri et al.,24 1984 | Finland | 73 women with twin pregnancies Randomization: based on year of birth Allocation concealment: not mentioned Loss to follow-up: 5 women excluded from experimental group owing to program refusal Recruitment dates: 1979–1980 | Experimental group: routine hospital rest Gestational age at study start > 29 wk Length: until delivery (mean 36.7 [SD 2.4] wk) n = 28 Control group: specialized outpatient antenatal care; weekly clinic visits; admitted to hospital if complications occurred Gestational age at study > 29 wk Length: until delivery (mean 37.4 [SD 1.8] wk) n = 45 | Infant: perinatal death, preterm birth (< 37 wk), gestational age, birth weight < 2500 g, birth weight < 1500 g Maternal: pregnancy-induced hypertension |
| Hobel et al.,28 1994 | US | 1774 women at high risk for preterm birth based on scoring of risk factors at < 31 weeks’ gestation Women in intervention hospitals were randomized to 1 of 5 interventions Randomization: method not described Allocation concealment: not described Loss to follow-up: not described | 1. Experimental group: bed rest at home 2. Control group 1: placebo 3. Progestin: women administered progestin; not included in meta-analyses 4. Social support: women given social support; not included in meta-analyses 5. Control group 2: no intervention Length: < 31 wk until birth All participants in intervention hospitals were given education intervention consisting of identification of preterm labour, steps to take if signs of preterm labour occurred and prevention strategies | Infant: preterm birth (< 37 wk) Maternal: none |
| Laurin et al.,30 1987 | Sweden | Women with singleton pregnancies with estimated weight deviation (suspected intrauterine growth restriction) of > 20% at 32 weeks’ gestation or > 15% at 34 weeks’ gestation Randomization: quasi-random based on even and odd year of birth (maternal) Allocation: not described Loss to follow-up: 15/49 in experimental group and 8/58 in control group did not fulfill requirements of their allocation Recruitment dates: 1982–1983 | Experimental group: admitted to hospital; advised to rest in bed 22 h per day; allowed to rest at home on weekends Gestational age at study start < 35 wk Length: > 3 wk on average n = 34 Control group: normal activity at home; discontinuation of work duties Gestational age at study start < 35 wk Length: > 4 wk on average n = 50 | Infant: perinatal death, birth weight, gestational age Maternal: cesarean delivery |
| Leung et al.,27 1998 | Hong Kong | 88 women with singleton pregnancies at 28–38 weeks’ gestation with diastolic blood pressure 90–100 mm Hg Randomization: not described Allocation concealment: consecutively numbered opaque, sealed envelopes Loss to follow-up: infant outcomes for 13 pregnancies in experimental group and 8 pregnancies in control group not presented owing to lack of hypertension Exclusion criteria: proteinuria or symptoms of severe preeclampsia Recruitment dates: May 1995–November 1996 | Experimental group: admitted to hospital and advised to rest in bed as much as possible Mean gestational age at study start 33.2 (SD 2.9) wk n = 44 Control group: normal activity at home; daily proteinuria testing at home and weekly clinic visits; admitted to hospital if proteinuria, severe preeclampsia or fetal growth restriction developed Mean gestational age at study 33.1 (SD 3.0) wk n = 44 | Infant: birth weight, birth weight < 2500 g, SGA, admission to NICU (reported only for pregnancies in which hypertension developed [31 inpatients and 36 outpatients]) Maternal: cesarean delivery, pregnancy-induced hypertension |
| MacLennan et al.,25 1990 | Australia | 141 women with multiple-gestation pregnancies (twins) Randomization: computer-generated list of random numbers Allocation concealment: patient and research coordinator blinded to allocation number meaning Exclusion criteria: hypertension, polyhydramnios, antepartum hemorrhage, preterm labour or rupture of membranes. Loss to follow-up: 13/69 participants allocated to experimental group did not complete study Recruitment dates: not specified | Experimental group: in hospital from 26 to 30 weeks’ gestation; allowed to leave on weekends Mean gestational age at study start 26.0 (SD 2.1) wk Length: 4 wk n = 69 Control group: advised to continue normal activities at home and visit clinic every 2 wk Mean gestational age at study start 26.0 (SD 2.1) wk Length: 4 wk n = 72 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, birth weight < 2500 g, birth weight < 1500 g, admission to NICU Maternal: cesarean delivery, pregnancy-induced hypertension, PROM, GDM |
| Mathews,26 1977 | UK | 135 women with singleton pregnancies complicated by mild nonalbuminuric and nonsymptomatic hypertension (diastolic blood pressure 90–109 mm Hg) after 28 weeks’ gestation Randomization: randomized; method not described Allocation concealment: previously prepared cards in envelopes Loss to follow-up: patients excluded from trial if they refused hospital admission | Sedated group Experimental group: admitted to hospital and kept in bed aside from meals and toileting; administered phenobarbitone, 15 mg 3 times daily Gestational age at study start > 28 wk Length: 97.2% delivered after 37 wk n = 36 Control group: advised to resume normal activity at home; administered phenobarbitone, 15 mg 3 times daily Gestational age at study start > 28 wk Length: 97.2% delivered after 37 wk n = 36 Nonsedated group Experimental group: admitted to hospital and kept in bed aside from meals and toileting Gestational age at study start > 28 wk Length: 97.1% delivered after 37 wk n = 35 Control group: advised to resume normal activity at home Gestational age at study start > 28 wk Length: 100% delivered after 37 wk n = 28 | Infant: perinatal death, preterm birth (< 37 wk), very preterm birth, birth weight, gestational age, birth weight < 2500 g, SGA Maternal: cesarean delivery, pregnancy-induced hypertension |
Notes: GDM = gestational diabetes mellitus, NICU = neonatal intensive care unit, PPROM = preterm premature rupture of membranes, PROM = premature rupture of membranes, SD = standard deviation, SGA = small for gestational age.