A Cochrane review included 5 studies with a total of 971 preterm infants with mean gestational ages at birth from 29 to 35 weeks. No studies comparing the intervention in the term newborn population were found. All studies compared cup versus bottle feeds as a supplement to breastfeeding when transitioning from full nasogastric feeds to full breastfeeds. Two studies reported results for weight gain, and there was no statistically significant difference between groups. Two studies reported average time to feed which showed no difference between groups. Two studies assessed length of hospital stay and there was considerable variation in results and in the direction of effect. Results for not breastfeeding at different time points favoured cup feeding, and are shown in table .
| Outcome | Participants (studies) | RR (95% CI) |
|---|---|---|
| 1) statistical heterogeneity, I2=72%; 2) I2=57%; 3) I2=55% | ||
| Not breastfeeding at hospital discharge | 957 (4 studies) | 0.64 (0.49 to 0.85)1) |
| Not fully breastfeeding at hospital discharge | 893 (4 studies) | 0.61 (0.52 to 0.71)2) |
| Not breastfeeding at 3 months | 883 (3 studies) | 0.83 (0.71 to 0.97) |
| Not breastfeeding at 6 months | 803 (2 studies) | 0.83 (0.72 to 0.95)3) |
Comment: The quality of evidence is downgraded by study limitations (lack of blinding), and by inconsistency (variability in results).