Oral Calcium in Pregnant Women With Hypertension

Hypertension Clinical Trial

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00000543
• Other study ID #: 86
• Secondary ID: R01HL048846
• Status: Completed
• Phase: Phase 2
• First received: October 27, 1999
• Last updated: May 12, 2016
• Start date: August 1993
• Est. completion date: July 1999

Study information

• Verified date: April 2002
• Source: National Heart, Lung, and Blood Institute (NHLBI)
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Interventional

Clinical Trial Summary

To determine of providing calcium supplementation to women with pre-existing hypertension reduces the level of blood pressure, requirement for antihypertensive drugs, and incidence of pre-eclampsia.

Description:

BACKGROUND:

Maternal and fetal complications are more likely to occur in pregnant women with preexisting hypertension. Alterations in calcium metabolism, the renin angiotensin system, and intracellular free calcium concentration have been identified in this high risk population. The beneficial effects of calcium supplementation on blood pressure and the incidence of superimposed pre-eclampsia may be due to correction of the hormonal and cellular basis for vasoconstriction. The trial sought to prove that oral calcium lowered parathyroid hormone, reduced intracellular free calcium, and decreased vascular endothelin production, resulting in vasodilation and compensatory stimulation of the renin-angiotensin system.

DESIGN NARRATIVE:

Randomized. Double blind. In this observational study, subjects were assigned to two grams of supplemental elemental calcium or to placebo at 13 to 15 weeks gestation. The trial determined the effect of oral calcium supplementation on: the level of blood pressure; the need for antihypertensive drugs; forearm and peripheral vascular resistance; the incidence of maternal complications, including pre-eclampsia and eclampsia; and plasma levels of vitamin D3, ionized calcium, parathyroid, renin activity, angiotensin II, endothelin, nitrate/nitrite, prostacyclins, and intracellular calcium concentrations in lymphocytes and platelets. These variables were measured prior to randomization and every two months throughout pregnancy and the postpartum. Support ended in July 1999.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 0
• Est. completion date: July 1999
• Accepts healthy volunteers: No
• Gender: Female
• Age group: 18 Years to 40 Years
• Eligibility: Pregnant women with chronic hypertension.

Study Design

Allocation: Randomized, Masking: Double-Blind, Primary Purpose: Prevention

Related Conditions & MeSH terms

• Cardiovascular Diseases
• Heart Diseases
• Hypertension
• Pre-Eclampsia
• Pregnancy Toxemias
• Vascular Diseases

Intervention

Behavioral:
• dietary supplements

Drug:
• calcium

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
National Heart, Lung, and Blood Institute (NHLBI)

References & Publications (3)

Curnow KM, Pham T, August P. The L10F mutation of angiotensinogen is rare in pre-eclampsia. J Hypertens. 2000 Feb;18(2):173-8. — View Citation

Hojo M, August P. Calcium metabolism in normal and hypertensive pregnancy. Semin Nephrol. 1995 Nov;15(6):504-11. Review. — View Citation

Hojo M, Suthanthiran M, Helseth G, August P. Lymphocyte intracellular free calcium concentration is increased in preeclampsia. Am J Obstet Gynecol. 1999 May;180(5):1209-14. — View Citation