Table 1.
Characteristics and methods of studies included in the review (n = 15).
| First Author (Year) |
Risk of Bias |
Country of Study |
No. of Centers (n) |
Infants Enrolled (n) |
Group Allocation | Mean Gestational Age (Weeks) | Mean Birth Weight (Grams) |
Follow Up | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| I a/I b | C/R c | I a/I b | C/R c | I a/I b | C/R c | ||||||
| Melnyk et al. (2001) [19] | Low | United States | 1 | 42 | 20 | 22 | 31.4 | 31.6 | 1482.7 | 1731.0 | |
| Ramanathan Paul, Deorari, Taneja, and George (2001) [20] | Low | India | 1 | 24 | 14 | 14 | (median) 30.4 |
(median) 30.9 |
1219.0 | 1270.9 | |
| Browne and Talmi (2005) [17] | Low | United States | 1 | 84 | 28 a/31 b | 25 | 32.0 a/31.2 b | 31 | 1617.4 a/ 1509.3 b |
1518.0 | |
| Lai et al. (2006) [21] | Low | Taiwan | 2 | 30 | 15 | 15 | 33.8 | 2248 | |||
| Miles, Cowan, Glover, Stevenson, and Modi (2006) [22] | Low | United Kingdom | 2 | 78 | 42 | 32 | 28 | 28 | 1086 | 1133 | |
| Schroeder and Pridham (2006) [23] | Some concerns |
United States | 2 | 16 | 8 | 8 | 26.8 | 27.5 | 828 | 1049 | |
| Glazebrook et al. (2007) [24] |
High | United Kingdom | 6 | 210 | 99 | 111 | 20 | 21 | (median) 1120 |
(median) 1220 |
|
| Borghini et al. (2014) [25] | Low | Switzerland | 1 | 83 | 30 | 30/23 c | 30 | 30/39 c | 1343 | 1435/3281 | 12 months CA |
| Wu et al. (2014) [18] | Low | Taiwan | 3 | 178 | 57 a/63 b | 58 | 30.0 a/29.9 b | 29.3 | 1179 a/1149 b | 1091 | 24 months |
| Hoffenkamp et al. (2015) [26] | Low | Netherlands | 7 | 150 | 75 | 75 | 32 | 32 | 1828 | 1770 | at 1, 3, and 6 months postpartum |
| Mörelius, Örtenstrand, Theodorsson, and Frostell (2015) [27] | Low | Sweden | 2 | 42 | 23 | 19 | 34 | 34 | 2468 | 2512 | at 1 and 4 months CA |
| Samra et al. (2015) [28] | Low | United States | 1 | 40 | 20 | 20 | 35 | 35.5 | 2493 | 2693.8 | at discharge |
| Evans, Boyd, Colditz, Sanders, and Whittingham (2017) [29] | Low | Australia | 2 | 145 | 75 | 70 | 28.51 | 28.55 | 1159.3 | 1107.8 | at 12 months CA |
| Heo and Oh (2019) [30] | Some concerns |
South Korea |
1 | 66 | 33 | 33 | 28.42 | 29.75 | 1139.6 | 1228.1 | |
| Twohig et al. (2021) [31] | Some concerns |
Ireland | 1 | 80 | 42 | 38 | 28.4 | 28.3 | 1179 | 1176 | at 6,9, and 12 months CA |
Note. C: control group; CA: corrected age; I: intervention group (I a/I b = 1st Intervention Group/2nd Intervention Group); R c: reference group (full-term infants).