Bone Accrual and Hormones in Response to Lactation
Bone Accrual and Hormones in Response to Lactation
This is a prospective observational trial of healthy postpartum women to investigate changes
 in bone density and markers of bone turnover during lactation. The study hypothesis is that
 women who breast-feed 5 months or more will lose bone density and subsequently regain the
 bone density after weaning. This study seeks to define determinants of the regain in bone
 density.
This is a prospective observational trial enrolling healthy postpartum women, ages 20 years
 and older with the intent to breast-feed from the UNC outpatient obstetrical clinics and the
 UVA outpatient obstetrical clinics. These women were studied at 3-5 visits in the year
 following their delivery to assess bone density, nutritional intake, exercise, and
 breast-feeding choices. The number of study visits depended on the timing of return of menses
 and interest in participating in the follow-up study (timepoints are: immediate postpartum, 3
 months postpartum, return of menses, 6 months after return of menses and follow-up visit 6
 months after final visit). Blood was taken for analysis of bone-related hormones, bone
 turnover and calcium homeostasis markers. The study focuses on women with extended lactation
 (at least 5 months of lactation) whereas women who cease lactation prior to 3 months will be
 the primary comparison group.
Inclusion Criteria:

 -  age >20 at the time of delivery

 -  singleton pregnancy and

 -  <2 prior pregnancies that were >20 weeks gestation.

 Exclusion criteria:

 -  maternal rheumatologic disorders

 -  maternal anorexia nervosa

 -  maternal endocrinologic disorders,

 -  medications known to affect bone density such as corticosteroids, thyroid hormone use,
 anticonvulsant therapy, bisphosphonates, long-term GnRH agonists use and calcitonin.

 -  Subsequent pregnancy during the study