[1] Natl Inst Publ Hlth, Nutr & Hlth Res Ctr 1, Mexico City, DF, Mexico
[2] Natl Inst Publ Hlth, Nutr & Hlth Res Ctr, Mexico City, DF, Mexico
[3] Univ Iberomar, Dept Hlth, Mexico City, DF, Mexico
[4] Natl Inst Publ Hlth, Evaluat Surveys Ctr, Mexico City, DF, Mexico
[5] Minist Hlth, Maternal & Perinatal Hlth, Mexico City, DF, Mexico
[6] WHO, Geneva, Switzerland