Dietary Calcium Supplementation to Reduce Blood Lead in Pregnancy

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00558623
Recruitment Status : Completed
First Posted : November 15, 2007
Last Update Posted : November 15, 2007
Mexican National Institute of Public Health
Brigham and Women's Hospital
University of California, Santa Cruz
Information provided by:
National Institute of Environmental Health Sciences (NIEHS)

Brief Summary:
Lead accumulates in bone. During pregnancy, physiologic changes occur prompting bone resorption in order to provide calcium to the growing fetal skeleton also release the lead stored in bone into a pregnant woman's circulation. We have previously demonstrated that lead stores mobilized into the circulation of pregnant women pose a major threat to fetal development. This is particularly unfortunate since bone lead stores, once accumulated, persist for decades, thereby jeopardizing the pregnancies of women even if their current lead exposures have subsided. What then can be done for the many thousands of women who have had lead exposure while growing up and who want to have healthy children? To address this question, in 2000, this project embarked on a randomized intervention trial to test whether a bedtime nutritional supplement of 1,000 mg of calcium can significantly reduce fetal lead exposure and toxicity by suppressing bone resorption in the pregnant mother.

Condition or disease Intervention/treatment Phase
Lead, Blood Pregnancy Bone Resorption Dietary Supplement: calcium carbonate Not Applicable

Detailed Description:

Recent evidence indicates that there is a marked increase in the mobilization of lead from maternal bone stores into circulation during pregnancy and lactation. Furthermore, data from our group and others indicate that this phenomenon carries a significant risk of fetal toxicity in the form of growth (decreased birth weight, head circumference, birth length) and subsequent cognitive development. These findings pose a major public health problem, even among societies with declining lead exposure, given the persistence of pockets of high lead exposure (including some communities living in proximity to hazardous waste) as well as the long residence time of lead in bone (years to decades). One possible strategy for suppressing the mobilization of maternal bone lead stores during pregnancy is nutritional intervention. We are conducting a randomized, double-blinded, placebo-controlled trial of dietary supplements containing 1,200 milligrams of calcium as a means of suppressing bone resorption and the resulting mobilization of lead from bone into plasma during pregnancy, and into breast milk during the postpartum period. We are taking maternal measurements of pre-pregnancy and postpartum bone lead using our K-x-ray fluorescence technology; bone resorption (by assaying N-telopeptide of type I collagen in urine [urinary NTX]), whole blood lead, and plasma lead (using special collection techniques and measured by IDTIMS) during pre-pregnancy, the first, second, third trimesters and at one and four months postpartum; and breast milk lead levels at one and four months postpartum.

We are measuring maternal plasma and breast milk lead levels as these are the most direct sources of fetal and infant lead exposures, and recent research suggests that maternal venous blood lead levels do not adequately reflect either of these parameters. We are testing the hypothesis that supplements will significantly decrease urinary NTX, plasma lead, and breast milk lead levels. We are also exploring the relationship of plasma lead levels to birth anthropometry measures. This research, if successful, may provide a means of preventing secondary toxicity from accumulated lead burdens among women of reproductive age.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 670 participants
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Controlled Trial in Pregnancy of Dietary Supplements for Suppression of Bone Resorption and Mobilization of Lead Into Plasma
Study Start Date : January 2001
Actual Study Completion Date : April 2005

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Placebo Comparator: 1
Dietary Supplement: calcium carbonate
daily supplement of 1,200 milligrams calcium (two-600 mg tablets calcium carbonate at bedtime)
Other Name: Lederle, Inc.

Primary Outcome Measures :
  1. Blood Lead Concentration, Plasma Lead Concentration [ Time Frame: 2nd, 3rd trimester pregnancy and 1,4,7,12 months postpartum ]

Secondary Outcome Measures :
  1. Urinary Cross-linked N-telopeptides (marker of bone resorption) [ Time Frame: 2nd, 3rd trimester of pregnancy and 1,4,7,12 months postpartum ]

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Ages Eligible for Study:   Child, Adult, Older Adult
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • being in the first trimester of pregnancy (no more than 14 weeks gestation); not presenting with a high-risk pregnancy; residing and plans to reside in the metropolitan Mexico City area for approximately 5 years; agreeing to participate and signing the informed consent form.

Exclusion Criteria:

  • high-risk pregnancy

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00558623

Mauricio Hernandez-Avila
Cuernavaca, Morelos, Mexico, 62100
Sponsors and Collaborators
National Institute of Environmental Health Sciences (NIEHS)
Mexican National Institute of Public Health
Brigham and Women's Hospital
University of California, Santa Cruz
Principal Investigator: Howard Hu, MD, ScD Harvard School of Public Health and University of Michigan
Principal Investigator: Mauricio Hernandez-Avila, MD, ScD National Institute of Public Health and Ministry of Health, Mexico

Publications automatically indexed to this study by Identifier (NCT Number): Identifier: NCT00558623     History of Changes
Other Study ID Numbers: P10345/9910CONT
NIEHS P42-ES05947 (Project 1)
First Posted: November 15, 2007    Key Record Dates
Last Update Posted: November 15, 2007
Last Verified: November 2007

Keywords provided by National Institute of Environmental Health Sciences (NIEHS):
lead, blood
randomized trial
dietary supplementation
bone resorption

Additional relevant MeSH terms:
Bone Resorption
Bone Diseases
Musculoskeletal Diseases
Calcium, Dietary
Calcium Carbonate
Bone Density Conservation Agents
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Gastrointestinal Agents