Fig 4 Probiotic supplementation during pregnancy or infancy and lower respiratory tract infection in children. The longest available follow-up data (intention to treat) were extracted from each contributing trial. Trials are sorted in order of decreasing duration of follow-up, and subgrouped according to whether the incidence of lower respiratory tract infection was systematically reported as a primary or secondary outcome, or as an adverse event. AE=adverse event; df=degrees of freedom; LRTI=lower respiratory tract infection; M-H=Mantel-Haenszel