Hypocalciuria in hypertensive disorder in pregnancy and how to measure it.

We studied the urinary calcium excretion in 41 patients in the third trimester of pregnancy. There was a significant decrease in 24-hour calcium excretion in hypertensive and pre-eclamptic patients. The 24-hour calcium excretion correlated well with the calcium to creatinine ratio of a single voided urine sample. We conclude that measuring urinary calcium excretion may be valuable in the care and the study of pregnant patients with hypertensive disorders, and that the 24-hour urinary calcium excretion can be estimated from a single voided urine sample.