S4	S1 AND S2 AND S3	117
S3	(MH "Caffeine") OR caffeine OR caffedrine OR coffein OR cafeine OR methylxanthine OR trimethylxanthine	6725
S2	randomized controlled trial OR controlled clinical trial OR randomized OR randomised OR placebo OR clinical trials as topic OR randomly OR trial OR PT clinical trial	587,317
S1	infant or infants or infant’s or infantile or infancy or newborn* or "new born" or "new borns" or "newly born" or neonat* or baby* or babies or premature or prematures or prematurity or preterm or preterms or "pre term" or premies or "low birth weight" or "low birthweight" or VLBW or LBW	520,047