Post hoc subgroup analysis showed a potential treatment effect of allopurinol on the proportion of infants with a cord S100 value above the 75th percentile in girls ( ALLO n = 5 ( 12 % ) vs CONT n = 10 ( 31 % ) ; risk ratio ( RR ) 0.37 ( 95 % CI 0.14 to 0.99 ) ) but not in boys ( ALLO n = 18 ( 32 % ) vs CONT n = 15 ( 25 % ) ; RR 1.4 ( 95 % CI 0.84 to 2.3 ) ) .