Vitamin D Supplements for Pregnant Women Should Be Customised to the Individual to Ensure Benefits Are Felt

Newswise — Vitamin D supplements are less effective at raising vitamin D levels in pregnant women if they deliver their babies in the winter, have low levels of vitamin D early in pregnancy or gain more weight during pregnancy, a new Southampton study has shown.

The findings, published the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism, showed pregnant women respond differently to vitamin D supplementation depending on their individual attributes.

The University of Southampton researchers suggest that supplement levels should be tailored according to individual risk factors.

Vitamin D is a hormone that helps the body absorb calcium. It plays a crucial role in bone and muscle health. The skin naturally produces vitamin D after exposure to sunlight but people also obtain smaller amounts of the vitamin through foods, such as milk fortified with vitamin D.

Evidence suggests vitamin D deficiency during pregnancy can harm maternal health, fetal development and the child’s long-term skeletal health.

Professor Nicholas Harvey, of the Medical Research Council Lifecourse Epidemiology Unit, University of Southampton, who led the study with Dr Rebecca Moon, Clinical Research Fellow, comments: “It is important for pregnant women to have sufficient levels of vitamin D for the health of their baby. Our study findings suggest that in order to optimise vitamin D concentrations through pregnancy, the supplemental dose given may need to be tailored to a woman’s individual circumstances, such as the anticipated season of delivery.”

The Maternal Vitamin D Osteoporosis Study (MAVIDOS), is a multi-centre, double-blind, randomised, placebo-controlled trial of vitamin D supplementation in pregnancy. More than 800 pregnant women were recruited and randomised to take either 1000 units (25 micrograms) of vitamin D every day or a matched placebo capsule from 14 week’s gestation until delivery of the baby.

Analysis showed that participants who received the vitamin D supplement achieved different levels of vitamin D in the blood, even though they received the same dose. Researchers found women who delivered in the summer, who gained less weight during pregnancy and who had higher vitamin D levels early in pregnancy tended to have higher levels of vitamin D in the blood than their counterparts. Women who consistently took the supplement also had higher levels of vitamin D than participants who did not.

“Our findings of varied responses to vitamin D supplementation according to individual attributes can be used to tailor approaches to antenatal care,” said Professor Cyrus Cooper, Director, and Professor of Rheumatology at the MRC Lifecourse Epidemiology Unit, University of Southampton. “This work forms part of a larger programme of research at the MRC Lifecourse Epidemiology Unit, University of Southampton, addressing the early life determinants of bone development, and will inform novel strategies aimed at improving bone health across future generations.”

The study was funded by the charity Arthritis Research UK, with further funding support from the MRC, National Institute for Health Research (NIHR) and the Bupa Foundation.

ENDS

Notes to Editors

1. The study, “Determinants of the Maternal 25-hydroxyvitamin D Response to Vitamin D Supplementation During Pregnancy,” will be published online at http://press.endocrine.org/doi/10.1210/jc.2016-2869, ahead of print. A copy of the study is available from Media Relations upon request. DOI: 10.1210/jc.2016-2869

2. Other authors of the study include: Rebecca J. Moon, Stefania D’Angelo, Sarah R. Crozier, Hazel M. Inskip, Elaine M. Dennison and Sian M. Robinson of Southampton General Hospital in Southampton, U.K.; Inez Schoenmakers and Ann Prentice of the Elsie Widdowson Laboratory in Cambridge, U.K.; Nigel K. Arden, Andrew Carr and M. Kassim Javaid of the University of Oxford in Oxford, U.K.; Nicholas J. Bishop of Sheffield Children’s Hospital and the University of Sheffield in Sheffield, U.K.; Richard Eastell of the University of Sheffield in Sheffield, U.K.; Robert Fraser and Saurabh V. Gandhi of the Sheffield Hospitals NHS Trust in Sheffield, U.K.; Keith M. Godfrey of Southampton General Hospital and the University of Southampton in Southampton, U.K.; Stephen Kennedy and Aris T. Papageorghiou of John Radcliffe Hospital at the University of Oxford in Oxford, U.K.; M. Zulf Mughal of Royal Manchester Children’s Hospitals in Manchester, U.K.; and David M. Reid at the University of Aberdeen in Aberdeen, U.K.

3. The Maternal Vitamin D Osteoporosis Study (MAVIDOS) started in September 2008 and recruited more than 1,000 women over three centres (Southampton, Sheffield and Oxford). Women who agreed to take part and had Vitamin D levels in the low-normal range, were randomised at 14 weeks gestation to either 1,000 units of Vitamin D daily or to a matched placebo tablet for the duration of pregnancy. Bone mass in the baby was assessed using a bone density (DXA) scanner. For more information visit http://www.mrc.soton.ac.uk/index.asp?page=284

4. At Arthritis Research UK, we invest in breakthrough treatments, the best information and vital support for everyone affected by arthritis. We believe that by harnessing the power of exceptional science we can overcome the pain, isolation and fatigue arthritis causes, making everyday life better for all 10 million people with arthritis in the UK.For more information, please visit www.arthritisresearchuk.org Twitter: www.twitter.com/arthritisRUK Facebook: www.facebook.com/arthritisresearchuk

5. The Medical Research Council is at the forefront of scientific discovery to improve human health. Founded in 1913 to tackle tuberculosis, the MRC now invests taxpayers’ money in some of the best medical research in the world across every area of health. Thirty-one MRC-funded researchers have won Nobel prizes in a wide range of disciplines, and MRC scientists have been behind such diverse discoveries as vitamins, the structure of DNA and the link between smoking and cancer, as well as achievements such as pioneering the use of randomised controlled trials, the invention of MRI scanning, and the development of a group of antibodies used in the making of some of the most successful drugs ever developed. Today, MRC-funded scientists tackle some of the greatest health problems facing humanity in the 21st century, from the rising tide of chronic diseases associated with ageing to the threats posed by rapidly mutating micro-organisms. www.mrc.ac.uk

6. The National Institute for Health Research (NIHR) is funded by the Department of Health to improve the health and wealth of the nation through research. Since its establishment in April 2006, the NIHR has transformed research in the NHS. It has increased the volume of applied health research for the benefit of patients and the public, driven faster translation of basic science discoveries into tangible benefits for patients and the economy, and developed and supported the people who conduct and contribute to applied health research. The NIHR plays a key role in the Government’s strategy for economic growth, attracting investment by the life-sciences industries through its world-class infrastructure for health research. Together, the NIHR people, programmes, centres of excellence and systems represent the most integrated health research system in the world. For further information, visit the NIHR website (www.nihr.ac.uk).

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