Characteristics of the included studies
| Study ID | Patient population | Mean/median GA (weeks) mean birth weight (g) | Intervention vs Control sample size | Baseline characteristics | Primary outcome |
| UCM vs DCC | |||||
| Rabe et al 17 | 24–32 6/7 weeks | 29.5±2.7 vs 29.2±2.3 weeks 1235±468 vs 1263±428 g | I-UCM vs DCC 58 (27 vs 31) | CS: 78% vs 58% Resuscitation: Intubation: 55% vs 52% APGAR at 5 min: 8 vs 9 | Hematocrit and haemoglobin at 1 hour after birth (I-UCM vs DCC): 0.52 vs 0.51, p=0.65 and 17.5 g/L vs 17.3 g/L, p=0.71 |
| Rabe et al 45 | Follow-up of Rabe 2011 at 2 years and 3.5 years | I-UCM vs DCC 39 (22 vs 17) at 2 years 29 (18 vs 11) at 3.5 years | 2--year Bayley III scores (I-UCM vs DCC): cognitive: 119±17.5 vs 111±25.7, p=0.08; language: 108±18.3 vs 95±21.5, p=0.05; motor: 105±14.8 vs 102±18.8, p=0.39 3.5 years: Bayley III scores: cognitive: 127±19.8 vs 120±26.6, p=0.62; language: 115±18.1 vs 106±22.8, p=0.11; motor: 114±23.0 vs 108±20.9, p=0.3 | ||
| Katheria et al 16 | 23–31 6/7 weeks | 28±2 vs 28±2 weeks 1255±413 vs 1132±392 g | I-UCM vs DCC 154 (CS delivered) (75 vs 79) | CS rate 100%. Resuscitation details: IPPV : 57% vs 56% Intubation: 28% vs 33% APGAR at 1, 5 min: 5,7 | SVC flow with in first 12 hours (I-UCM vs DCC): 93 vs 81 mL/kg/min, p<0.05 |
| Katheria et al 46 | Follow-up study of Katheria 2015 at 22–26 months of age | I-UCM vs DCC 135 (70 vs 65) | At 22–26 months (I-UCM vs DCC): Bayley III scores: cognitive: 100±13 vs 95±12, p=0.031; language: 93±15 vs 87±13, p=0.013; motor: 99±12 vs 97±12, p=0.349 | ||
| Shirk et al 18 | 23–34 weeks | 32.1 (29.5 to 34) vs 32.0 (29.2 to 34) weeks 1620±587 vs 1579±576 g | I-UCM vs DCC 204 (100 vs 104) | CS: 54% vs 49% APGAR at 1,5 min: 7,8 vs 7,9 | First hematocrit after birth (I-UCM vs DCC)=51.8% vs 49.9%, p=0.07 |
| Finn et al 15 | <32 weeks | 28.4 (25.7 to 29.6) vs 28 (26.4 to 29.6) weeks 930 (700 to 1545) vs 925 (630 to 1490) g | I-UCM vs DCC 32 (18 vs 14) | APGAR at 1 min; 5 vs 6 | Cerebral EEG activity (burst ratio) at 6 hours (I-UCM vs DCC): 83% vs 68%, p=0.27. Regional cerebral oxygenation at 6 hours (I-UCM vs DCC)=83% vs 85%, p=0.94 |
| Katheria et al 8 | 23–31 weeks | 28.4±2.4 vs 28.4±2.5 weeks | I-UCM vs DCC 474 (236 vs 238) | CS:76% vs 67% | Death or severe IVH (I-UCM vs DCC):=29/236 (12%) vs 20/238 (8%), p=0.16 Severe IVH (I-UCM vs DCC): =20/236 (8%) vs 8/238 (3%), p=0.02 |
| UCM vs ICC | |||||
| Hosono et al 22 | 24–28 weeks | 27.0±1.5 vs 26.6±1.2 weeks 836±223 vs 846±171 g | I-UCM vs ICC 40 (20 vs 20) | 1 min APGAR score higher in milking group CS-70% vs 70% | Probability of not needing transfusion (I-UCM vs ICC): p=0.03 Total number of RBC transfusions (I-UCM vs ICC): 1.7 vs 4.0, p=0.02 |
| March et al 29 | 24–28 weeks | 27.0 (25.5 to 28.1) vs 26.3 (25.1 to 27.1) weeks : 755 (687.5 to 980) vs 770 (650 to 940) g | I-UCM vs ICC 75 (36 vs 39) | CS-55.6% vs 66.7% Intubation rate :100% in both groups APGAR at 1, 5 min: 4, 6 vs 4, 7 | Need of packed RBC transfusion in first 28 days of life (I-UCM vs ICC): 83.3% vs 97.4%, p=0.05 |
| Alan et al 19 | ≤32 weeks and ≤1500 g | 28.4±1.8 vs 28.0±1.9 weeks 1103±236 vs 1101 ±262 g | I-UCM vs ICC 44 (22 vs 22) | CS-86.4% vs 81.8% APGAR at 1, 5 min: 7, 8 vs 7, 8 | No. of packed RBC transfusions in the first 35 days of age (median) (I-UCM vs ICC): 2 vs 2, p=0.84 |
| Josephsen et al 23 | 24–27 6/7 weeks | 26.5±1.4 vs 26.1±0.9 weeks 914±208 vs 809±178 g | I-UCM vs ICC 25 (13 vs 12) | Not specified | Initial infant haemoglobin (I-UCM vs ICC): 139 g/L vs 134 g/L, p=0.62 |
| Katheria 201424 | 23–31 6/7 weeks | 28±2 vs 28±3 weeks 1170±356 vs 1131 ±396 g | I-UCM vs ICC 60 (30 vs 30) | CS-60% vs 44% APGAR at 1, 5 min: 5,.7 vs 6, 7 | SVC flow at <6 hours, 12–24 hours and 24–36 hours (I-UCM vs ICC): significant difference at <6 hours and at 24–36 hours, p<0.05 |
| Kumar et al 26 | 32–36 6/7 weeks | 34.7±1.3 vs 34.5±1.5 weeks 2397±268 vs 2354±274 g | C-UCM vs ICC 200 (100 vs 100) | CS-44% vs 39% APGAR at 1 min: 7 vs 7 | Haemoglobin and serum ferritin at 6 weeks of life (C-UCM vs ICC): 121±15 vs 104±12 g/L, p<0.01 and 428.9±217 vs 237.5±118, p<0.01 |
| Kilicdag et al 25 | <32 weeks | 30.2±1.9 vs 31.0±1.4 weeks 1495±409 vs 1661±351 g | I-UCM vs ICC 54 (29 vs 25) | 100% CS delivery APGAR at 1,5 min: 6, 8 vs 6,8 | Absolute neutrophil count on first day of life (I-UCM vs ICC): 5566 cells/µL vs 8120 cells/µL, p=0.032 |
| Song et al 32 | 24–32 6/7 weeks | 30.1±2.5 vs 29.0±2.6 weeks 1256±271 vs 1256±288 g | I-UCM vs ICC 66 (34 vs 32) | CS-70.6% vs 78.1% APGAR 1,5 min: 5,8 vs 5, 7 Intubation rate: 55.9% vs 46.9% | Initial haemoglobin (I-UCM vs ICC): 158±16 vs 147±21 g/L, p=0.018 |
| Alavi et al 20 | 28–34 weeks | 31.25±1.56 vs 31.35±1.86 weeks 2089±260 vs 2145±320 g | C-UCM vs ICC 80 (40 vs 40) | CS-20% vs 17.5% Resuscitation: IPPV: 12.5% vs 17.5% | Haemoglobin (g/L) and haematocrit at birth (C-UCM vs ICC): 170.9±8.7 vs 152.4±13.2, p=0.0001 and 51.16±1.57 vs 45.59±4.86, p=0.0001 |
| El-Naggar et al 21 | 24–31 weeks | 27.6±1.8 vs 27.2±2 weeks 1061±383 vs 1019±282 g | I-UCM vs ICC 73 (37 vs 36) | CS-56.8% vs 66.7% APGAR at 1, 5 min: 5, 7 vs 5, 7 IPPV: 84% vs 72% Intubation: 65% vs 58% | SVC flow at 4–6 hours after birth (I-UCM vs ICC): 88.9 mL/kg/min vs 107.3 mL/kg/min, p=0.13 |
| Lago Leal et al 27 | 24–36 6/7 weeks | Mean/Median GA not specified 1816±637 vs 2042±636 g | I-UCM vs ICC 138 (69 vs 69) | CS rate: not specified Resuscitation: not specified | Requirement of phototherapy (I-UCM vs ICC): 39/69 vs 24/69; RR, 95% CI 1.62 (1.12 to 2.38), p=0.01 |
| Li et al 28 | 28–37 weeks | 33.0 (28.5 to 36.4) vs 33.9 (29.3 to 36.2) weeks 1940±477 vs 1893±510 g | I-UCM vs ICC 102 (48 vs 54) | CS: 0% in both groups | Incidence of certain or probable infection in neonates with PPROM (I-UCM vs ICC): 40/48 (83.3%) vs 48/54 (88.9%), p=0.87 |
| Ram Mohan et al 30 | <33 weeks | 33.0 (27–36) vs 33.0 (29–36) weeks 1400 (945–3750) vs 1516 (760–2370) g | C-UCM vs ICC 60 (30 vs 30) | APGAR at 1, 5 min: 7,8 vs 6, 8 IPPV: 96.6% vs 86.6% Intubation: 10% vs 16.6% | Haemoglobin at 6 weeks of life (C-UCM vs ICC): 100.7±15.4 vs 89±26.3 g/L,p=0.003 Serum ferritin at 6 weeks of life (C-UCM vs ICC): 244.85±187.33 vs 148.54±162 ng/ml, p=0.04 |
| Silahli et al 31 | <32 weeks | Mean/Median GA not specified 1408±387 vs 1454±394 g | I-UCM vs ICC 75 (38 vs 37) | CS: 97% vs 78% | Thymic index in the first 24 hours of life (I-UCM vs ICC): 2.4 cm3 vs 2.8 cm3, p=0.077 |
CS, caesarean section; C-UCM, cut umbilical cord milking; EEG, Electroencephalogram; GA, gestational age; ICC, immediate cord clamping; IPPV, intermittent positive pressure ventilation; I-UCM, intact umbilical cord milking; IVH, Intraventricular haemorrhage; PPROM, Preterm premature rupture of the membranes; RBC, Red blood cell; SVC, Superior vena cava.