Bone Metabolism and Parathyroid Hormone-related Protein (PTHrP) Lactation Study

This study has been completed.
Information provided by (Responsible Party):
Mara Horwitz, University of Pittsburgh Identifier:
First received: January 31, 2007
Last updated: October 30, 2013
Last verified: October 2013

The primary aim of the study is to measure bone formation in both lactating and non-lactating post-partum women and compare these to those in healthy non-pregnant controls. The secondary aim is to obtain measurements of Parathyroid Hormone-related Protein (PTHrP), markers of bone resorption, and calcium and vitamin D metabolism in these subjects. The investigators believe that lactating women will have an increase in bone resorption but no increase in bone formation when compared to non-lactating post-partum women and normal controls.

Bone Diseases, Endocrine

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: A Prospective Cohort Pilot Study of Bone Metabolism in Lactating and Non-lactating Postpartum Women and Healthy Non-pregnant Women

Resource links provided by NLM:

Further study details as provided by University of Pittsburgh:

Primary Outcome Measures:
  • Measurements of amino-terminal telopeptides of procollagen 1 (P1NP), a marker of bone formation, in lactating and non-lactating postpartum women both at 6-8 and at 12-14 weeks post-partum, and to compare these values to those of normal controls [ Time Frame: 4 months ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Measurements of Parathyroid Hormone-related Protein (PTHrP), markers of bone turnover, calcium and vitamin D metabolism [ Time Frame: 4 months ] [ Designated as safety issue: No ]

Biospecimen Retention:   Samples Without DNA

archival blood serum and plasma

Enrollment: 49
Study Start Date: January 2007
Study Completion Date: June 2008
Primary Completion Date: June 2008 (Final data collection date for primary outcome measure)
3 groups
Group 1: post-partum breastfeeding women
Group 2
Group 2: post-partum bottlefeeding women
Group 3
Group 3: normal non-pregnant controls who are age and race-matched to Group 1

  Show Detailed Description


Ages Eligible for Study:   21 Years to 45 Years
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

New mothers who are either almost exclusively breast feeding or bottle feeding; normal controls to match those new mothers.


Inclusion Criteria:

  • Healthy Caucasian, Hispanic, or Asian women between the ages of 21-45.
  • Group 1: Postpartum (singleton pregnancy) women who are exclusively breastfeeding, defined as 1 or fewer bottles of supplemental formula/day.
  • Group 2: Postpartum (singleton pregnancy) women who are non-lactating, which is defined as bottle-feeding or having weaned their baby from breastfeeding for at least 4 weeks prior to study.
  • Group 3: Controls - Healthy, non-pregnant women who are race and age-matched to the breastfeeding women in group one. They may not have been lactating or pregnant within the last year.

Exclusion Criteria:

  • Subjects with cardiac, hypertensive, vascular, renal (serum creatinine of > 1.5), pulmonary, endocrine, musculoskeletal, hepatic, hematologic, or malignant or rheumatologic disease will be excluded from the study.
  • Smokers and those with a history of significant alcohol or drug abuse are excluded.
  • Baseline hypertension (systolic BP > 160 mm/Hg) or hypotension (systolic BP < 90 mm/Hg).
  • Subjects taking any chronic medications except stable doses of thyroid hormone, prenatal, vitamin supplements, or oral contraceptives.
  • Those who have received any investigational drug in past 90 days will be excluded from the study.
  • Women who are currently pregnant will be excluded from the study.
  • Women who became pregnant by in vitro fertilization IVF or any hormonal manipulation (i.e. fertility drugs such as clomid) are also excluded, as they may have an altered pre-pregnant hormonal state.
  • All women will have a urine pregnancy test performed at each of the two study visits and must not be pregnant in order to continue in the study.
  • Subjects are not allowed to donate blood between study visits.
  • In order to narrow the statistical variations in the study population, African-Americans are excluded because of demonstrated differences in renal excretion of calcium and vitamin D absorption.
  Contacts and Locations
Please refer to this study by its identifier: NCT00430417

United States, Pennsylvania
University of Pittsburgh
Pittsburgh, Pennsylvania, United States, 15213
Sponsors and Collaborators
University of Pittsburgh
Principal Investigator: Mara J Horwitz, MD University of Pittsburgh
  More Information


Responsible Party: Mara Horwitz, Associate Professor of Medicne, University of Pittsburgh Identifier: NCT00430417     History of Changes
Other Study ID Numbers: 0610073, R01DK073039
Study First Received: January 31, 2007
Last Updated: October 30, 2013
Health Authority: United States: Federal Government

Keywords provided by University of Pittsburgh:
Endocrine System Diseases
MusculoSkeletal System Disease
Physiologic Properties

Additional relevant MeSH terms:
Bone Diseases
Bone Diseases, Endocrine
Endocrine System Diseases
Musculoskeletal Diseases processed this record on April 20, 2014