Study	Reason for exclusion
Brantley 1980	Not a randomized or quasi‐randomized trial.
Faix 1988	Not a prophylaxis trial. Babies had NEC at entry, and were randomised to ampicillin and gentamicin vs ampicillin, gentamicin and clindamycin.
Fast 1994	No control arm. Interim report of trial in progress. Oral gentamicin vs an oral IgG/IgA mixture.
McCaffree 1975	Abstract only. Interim report of trial in progress. Insufficient data for analysis. Primary author could not be located for further data
Millar 1992	No control arm. In this study comparison was between vancomycin and aztreonam vs vancomycin and gentamicin, all drugs being given parenterally.