Pregnant women should be well nourished to support an infant’s development in utero. Surveys conducted throughout the world report both low levels of calcium intake and vitamin D insufficiency to be common in pregnancy.
Early life environment has long-term consequences for musculoskeletal development Harvey, N., E. Dennison, and C. Cooper, Osteoporosis: a lifecourse approach. J Bone Miner Res, 2014. 29(9): p. 1917-25.
Holroyd, C., et al., Epigenetic influences in the developmental origins of osteoporosis. Osteoporos Int, 2012. 23(2): p. 401-10.
. Poor early growth is associated with reduced adult bone mineral content (BMC) at peak bone mass and in later life Baird, J., et al., Does birthweight predict bone mass in adulthood? A systematic review and meta-analysis. Osteoporos Int, 2011. 22(5): p. 1323-34.
, as well as increased risk of hip fracture Cooper, C., et al., Maternal height, childhood growth and risk of hip fracture in later life: a longitudinal study. Osteoporos Int, 2001. 12(8): p. 623-9.
Javaid, M.K., et al., Growth in childhood predicts hip fracture risk in later life. Osteoporos Int, 2011. 22(1): p. 69-73.
The majority of bone development in the human foetus occurs during the third trimester, requiring a total of 30 g of calcium Namgung, R. and R.C. Tsang, Bone in the pregnant mother and newborn at birth. Clin Chim Acta, 2003. 333(1): p. 1-11.
. Intestinal absorption of calcium increases in the mother during pregnancy, and very low maternal intake may be a risk factor for lower bone mass in neonates, particularly in areas where dietary calcium content is chronically poor Ganpule, A., et al., Bone mass in Indian children--relationships to maternal nutritional status and diet during pregnancy: the Pune Maternal Nutrition Study. J Clin Endocrinol Metab, 2006. 91(8): p. 2994-3001.
. Although the general pattern of maternal diet during gestation appears related to offspring bone development, with more healthy maternal diets associated with greater offspring bone mass Cole, Z.A., et al., Maternal dietary patterns during pregnancy and childhood bone mass: a longitudinal study. J Bone Miner Res, 2009. 24(4): p. 663-8.
, the gestational micronutrient that has been most strongly associated with offspring bone development is vitamin D.
Vitamin D insufficiency is common during pregnancy. A UK study reported that 31% of mothers had insufficient (11–20 ng/mL) and 18% deficient (<11 ng/mL) circulating concentrations of 25-hydroxyvitamin D [25(OH)D] during late stage pregnancy Javaid, M.K., et al., Maternal vitamin D status during pregnancy and childhood bone mass at age 9 years: a longitudinal study. Lancet, 2006. 367(9504): p. 36-43.
. Lower concentrations of gestational 25(OH)D were associated with reduced whole-body and lumbar spine BMC and BMD in children at 9 years of age. In 2016, results were published from the UK Maternal Vitamin D Osteoporosis Study (MAVIDOS) Cooper, C., et al., Maternal gestational vitamin D supplementation and offspring bone health (MAVIDOS): a multicentre, double-blind, randomised placebo-controlled trial. Lancet Diabetes Endocrinol, 2016. 4(5): p. 393-402.
. This large-scale randomised-controlled trial was designed to test whether offspring of mothers supplemented with vitamin D during pregnancy have higher bone mass at birth than those of mothers who were not supplemented. Although there was no difference in whole body bone mineral content (BMC) between offspring of mothers supplemented with 1,000 International Units (IU) per day of cholecalciferol compared with offspring of mothers randomised to placebo, in a pre-specified secondary analysis, there was a large (0.5 SD) increase in neonatal BMC amongst offspring of supplemented mothers versus offspring of placebo mothers, for births occurring during winter months. The supplement appeared safe, and these findings suggest potential season dependent benefits for antenatal vitamin D supplementation.
In the USA the Dietary Guidelines Advisory Committee (DGAC) found that calcium and vitamin D are among several nutrients which are under-consumed relative to the Estimated Average Requirement (EAR) or the Adequate Intake (AI) levels set by the Institute of Medicine (IOM) Dietary Guidelines Advisory Committee: Scientific Report of the 2015 Dietary Guidelines Advisory Committee: Advisory Report to the Secretary of Health and Human Services and the Secretary of Agriculture. 2015 [Accessed 14.02.2019];
See link. Among pregnant women, 90% were found to have intakes below the EAR for vitamin D and 24% had intakes below the EAR for calcium. This led the DGAC to note specifically that calcium is an under-consumed nutrient of public health concern among pregnant women.
Strategies to achieve the Recommended Dietary Allowance (RDA) of vitamin D proposed by the American Academy of Pediatrics (AAP) and the Endocrine Society Golden, N.H. and S.A. Abrams, Optimizing bone health in children and adolescents. Pediatrics, 2014. 134(4): p. e1229-43.
Holick, M.F., et al., Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab, 2011. 96(7): p. 1911-30.
include consumption of fortified foods, broadening the range of fortified dairy products, and in some cases, the use of a vitamin D supplement or a multivitamin including vitamin D.
Strategies to improve calcium intake include increased consumption of dairy or fortified products that are important sources of calcium.
The National Health Service (NHS) in the UK recommends pregnant women should take a supplement containing 10 μg (400 IU) vitamin D each day throughout pregnancy and during breastfeeding National Health Service (NHS): Vitamins, Supplements and Nutrition in Pregnancy. [Accessed 14.02.2019];
See link. The recommendation highlights that women who choose to take a multivitamin supplement to obtain vitamin D should not use any supplements containing vitamin A (retinol), as too much could be harmful to the foetus. In 2014, the National Institute for Health and Clinical Excellence (NICE) published Public Health Guidance 56 on increasing vitamin D supplement use among at-risk groups, including pregnant women National Institute for Health and Care Excellence: Vitamin D: Supplement Use in Specific Population Groups. 2014 [Accessed 14.02.2019];