Abstract: We found three trials (involving 1915 babies) for inclusion in the review, but have included only two trials (involving 1302 healthy full-term breastfeeding infants) in the analysis. Meta-analysis of the two combined studies showed that pacifier use in healthy breastfeeding infants had no significant effect on the proportion of infants exclusively breastfed at three months (risk ratio (RR) 1.01; 95% confidence interval (CI) 0.96 to 1.07, two studies, 1228 infants), and at four months of age (RR 1.01; 95% CI 0.94 to 1.09, one study, 970 infants, moderate-quality evidence), and also had no effect on the proportion of infants partially breastfed at three months (RR 1.00; 95% CI 0.98 to 1.02, two studies, 1228 infants), and at four months of age (RR 0.99; 95% CI 0.97 to 1.02, one study, 970 infants). None of the included trials reported data on the other primary outcomes, i.e. duration of partial or exclusive breastfeeding, or secondary outcomes: breastfeeding difficulties (mastitis, cracked nipples, breast engorgement); infant's health (dental malocclusion, otitis media, oral candidiasis; sudden infant death syndrome (SIDS)); maternal satisfaction and level of confidence in parenting. One study reported that avoidance of pacifiers had no effect on cry/fuss behavior at ages four, six, or nine weeks and also reported no effect on the risk of weaning before age three months, however the data were incomplete and so could not be included for analysis. Pacifier use in healthy term breastfeeding infants, started from birth or after lactation is established, did not significantly affect the prevalence or duration of exclusive and partial breastfeeding up to four months of age. Evidence to assess the short-term breastfeeding difficulties faced by mothers and long-term effect of pacifiers on infants' health is lacking.

Plain-language summary: We updated the search on 30 June 2016. We identified three studies, with a total of 1915 babies. One study could not be included in the analysis and so findings are based on two studies involving 1302 infants. The mothers in the studies were motivated to breastfeed recruited immediately after birth and at two weeks of life, respectively. We found that unrestricted use of a pacifier did not affect the proportion of infants exclusive or partial breastfeeding at three and four months. The studies were remarkably consistent. We judged this to be moderate-quality evidence. There was no information on the effect of pacifier use on any breastfeeding difficulties experienced by the mothers, maternal satisfaction, infant crying and fussing and infant problems such as otitis media and dental malocclusion. In motivated mothers, there is moderate-quality evidence that pacifier use in healthy term breastfeeding infants before and after lactation is established does not reduce the duration of breastfeeding up to four months of age. However, there is insufficient information on the potential harms of pacifiers on infants and mothers. Until further information becomes available on the effects of pacifiers on the infant, mothers who are well-motivated to breastfeed should be encouraged to make a decision on the use of a pacifier based on personal preference.