Kyozuka H, Murata T, Fukuda T, et al. - The correlation between prepregnancy calcium (Ca) intake and hypertensive disorder of pregnancy (HDP) was investigated in normotensive primiparas using data from the Japan Environment Children’s study (JECS), the largest birth cohort study. Categorization of a total of 33,894 normotensive Japanese primiparas, who were recruited for JECS between January 2011 and March 2014, was done into five groups in accordance to prepregnancy Ca intake quintiles (Q1 and Q5 were the lowest and highest Ca intake groups, respectively) to compare their basic background and obstetrics outcome. Findings suggest no correlation of prepregnancy Ca intake with an increased risk of new-onset hypertension among primiparas during pregnancy despite considerable recommendations regarding Ca intake for women of reproductive age.