Median [ interquartile range ( IQR ) ] weight change was EC : -1.1 ( 9.5 ) kg versus SC : -1.1 ( 7.5 ) kg ( 6 weeks to 6 months ) and EC : +1.0 ( 8.7 ) kg versus SC : +2.3 ( 9 ) kg ( prepregnancy to 6 months ) .