| MeSH |
Adult
Body Mass Index
Bone Density/drug effects
Bone Remodeling/drug effects
Breast Feeding
Calcium, Dietary/administration & dosage*
Diet
Dietary Supplements
Female
Gestational Age
Humans
Middle Aged
Placebos
Postpartum Period
Pregnancy
Prenatal Care/methods*
Radius
Recommended Dietary Allowances
Tibia
Tomography, X-Ray Computed/methods
Vitamin D/analogs & derivatives
Vitamin D/blood |
| Abstract |
Background:
Low calcium intake during pregnancy may cause maternal skeletal calcium mobilization to meet fetal needs. The Recommended Dietary Allowance (RDA) for calcium in nonpregnant, pregnant, or lactating women aged 19-50 y is 1000 mg/d; most women in the United States report consuming 60-80% of the calcium RDA. An insufficient calcium intake could increase maternal bone loss during pregnancy and reduce bone recovery postpartum.
Objectives:
The aim of this study was to determine the effect of maternal calcium supplementation on peripheral cortical and trabecular bone loss during pregnancy and bone gain postpartum.
Methods:
A total of 64 women were enrolled in the study at 16 wk of gestation and randomly assigned to receive 1000 mg Ca/d or placebo for the remainder of the pregnancy. Measurements were performed at 16, 26, and 36 wk of pregnancy and at 4 and 12 mo postpartum for serum 25-hydroxyvitamin D and markers of bone turnover. Trabecular and cortical bone mineral density (BMD) and content were assessed at the tibia and radius by peripheral quantitative computed tomography.
Results:
Mean ± SD daily calcium intake at baseline was 733 ± 350 mg; only 25% of the women met the RDA. Thirty women (47% of those enrolled) remained in the study at 12 mo postpartum. After controlling for baseline bone value, serum 25-hydroxyvitamin D concentrations, length of breastfeeding, and body mass index, the calcium group had significantly greater increases in radial total BMD (P = 0.02) and tibial cortical BMD (P = 0.03) at 12 mo postpartum than the placebo group. Trabecular and total BMD at the tibia trended toward higher values (P < 0.06) in the calcium group than in the placebo group in the same models.
Conclusions:
These data show that supplemental calcium provided during pregnancy may improve bone recovery postpartum in women consuming a typical US diet. A larger study is warranted to solidify the conclusions. This trial was registered at clinicaltrials.gov as NCT01145573.
Comment in
The quest for evidence for calcium requirements for bone during pregnancy and lactation[Am J Clin Nutr. 2019]. |
