Infants born to women after lifestyle advice were significantly less likely to have birth weight above 4000 g ( lifestyle advice 164/1075 ( 15 % ) v standard care 201/1067 ( 19 % ) ; 0.82 , 0.68 to 0.99 ; number needed to treat ( NNT ) 28 , 15 to 263 ; P = 0.04 ) .