Objective: To measure the ultrafiltrable and total plasma calcium in normal pregnancy and pregnancies complicated with hypertension and pre-eclampsia.
Patients and methods: Total and ultrafiltrable calcium concentrations were measured in maternal plasma from non-pregnant (35), normal pregnant (35), Pregnancy induced hypertension (35) and pre-eclamptic (20) women. Plasma total calcium level was measured by the o'cresolphthalein method. Ultrafiltrate of plasma was obtained using the Amicon MPS-1 micro-partition device.
Results: There was no significant difference in the plasma total calcium level between the non- pregnant group and the pregnant group (normal, hypertensive and pre-eclamptic). However there was a significant reduction in the ultrafiltrable (protein free and complexed) calcium level in the pregnant group compared to the non-pregnant group (1.15mmol/L +/- 0.23 Vs 1.25mmol/L +/- 0.13) p<0.05.
Conclusion: Measurement of the ultrafiltrable calcium in addition to total calcium assay may be more useful in assessing calcium status in normal and complicated pregnancies.