A previous analysis of the Project Viva cohort (eastern Massachusetts, 1999−2002 recruitment) found an association between higher second-trimester supplemental maternal calcium intake and lower systolic blood pressure in offspring at 6 months. The authors analyzed 5,527 systolic blood pressure measurements from 1,173 mother-child pairs from this same cohort when the children were aged 3 years. They estimated the change in offspring blood pressure for a 500-mg difference in maternal total, dietary-only, and supplemental-only calcium intake during the first 2 trimesters of pregnancy. Mean daily total calcium intake was 1,311 mg (standard deviation, 421) in the first trimester and 1,440 mg (standard deviation, 386) in the second trimester. Mean systolic blood pressure of the offspring at age 3 years was 92.1 mm Hg (standard deviation, 10.3). None of the maternal calcium intake measures during the first and second trimesters was associated with systolic blood pressure in the offspring. For example, for each 500-mg increment in maternal total elemental calcium intake in the second trimester, child's 3-year systolic blood pressure was 0.1 mm Hg lower (95% confidence interval: −0.9, 0.6). Maternal calcium intake during pregnancy was not associated with offspring blood pressure at the age of 3 years.