This is an individually randomized controlled trial of the impact on birth length ( primary outcome ) of the time at which a maternal nutrition intervention is commenced : Arm 1 : 3 mo preconception vs. Arm 2 : 12-14 wk gestation vs. Arm 3 : none .192 ( derived from 480 ) randomized mothers and living offspring in each arm in each of four research sites ( Guatemala , India , Pakistan , Democratic Republic of the Congo ) .