Large dose of vitamin D in pregnancy cuts premature births: research
Women should take up to ten times the current recommended dose of vitamin D during pregnancy, experts have said after it was found to cut premature birth by half.
Published: 8:00AM BST 01 May 2010
In Britain pregnant women and breastfeeding mothers are recommended to take ten micrograms of vitamin D daily but a study has suggested higher doses may be more beneficial.
Lack of vitamin D, which the body can make from sunlight in summer months in Britain, can cause rickets.
It has been estimated that two in ten adults in Britain could be deficient in vitamin D.
Vitamin D is found in foods like fortified cereals, eggs and fish but most people also need around 15 minutes of sunshine three times a week to ensure sufficient levels.
In the 1950s and 1960s it was thought vitamin D could cause birth defects but it is now known that it is vital for good health of the mother and the developing feotus.
Some pregnant women are advised to take doses of up to 25 micrograms a day but doctors have been cautious of higher doses as there is evidence that very high doses can cause calcium levels in the blood to rise causing nausea, thirst, dizziness and headaches.
In the study presented at the Pediatric Academic Societies annual meeting in Vancouver, in British Columbia, Canada, pregnant women were randomly assigned to take one of three doses of vitamin D daily.
The women took either ten microgram doses, 50 microgram doses, or 100 microgram doses.
They were monitored throughout, including calcium levels in their blood, and there were no ill effects at any of the prescribed doses. Their vitamin D levels before the study were the same.
The team from University of South Carolina found the women taking the highest dose were 50 per cent less likely to suffer from problems including premature labour, pre-eclampsia, gestational diabetes and infections, than those on the lowest dose.
Dr Carol Wagner, lead author of the study, said: "The spectacular part of the study was it showed women replete in vitamin D had lower rates of preterm labor and preterm birth, and lower rates of infection."
She said the results showed the high dose was safe and effective so they could recommend all pregnant women take 1,000 micrograms of vitamin D daily.
Patrick O'Brien, spokesman for the Royal College of Obstetricians and Gynaecologists, said the study was interesting but the full data was needed before drawing conclusions.
"He added: "When giving vitamin D supplements in pregnancy there needs to be a degree of caution as there have been some theorectical concerns in the past that too much vitamin D could be harmful but the initial data from this study appears reassuring on this aspect."