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Optimal levels of vitamin D during pregnancy

Posted on: March 13, 2012   by  John Cannell, MD


More than 60 years ago, based on the science of the time (science that has stagnated for 60 years), Dr. E. Orbermer of Italy wrote the following:

“Until further experimental evidence, adequate and incontrovertible, is made available, I submit that we should play for safety. In a climate like that of England every pregnant woman should be given a supplement of vitamin D in doses of not less than 10,000 IU per day in the first 7 months, and 20,000 IU (per day) during the 8th and 9th months.”

OBERMER E. Vitamin-D requirements in pregnancy. Br Med J. 1947 Dec 6;2(4535):927.

The “adequate and incontrovertible evidence” that Dr. Orbermer wanted, to a certain extent, is finally here, 60 years later. As it has to do with developing human beings, it could not be more important. The study is the highest standard of proof, a randomized controlled trial, conducted by Professor Bruce Hollis and colleagues at the Medical University of South Carolina. They took 350 pregnant women, gave 1/3 of them 600 IU/day, 1/3 of them 2,000 IU/day, and 1/3 4,000 IU/day. Then they waited to see, among many things, which group would produce infants with at least 20 ng/ml of vitamin D in their blood, the lowest limit the 2010 Food and Nutrition Board (FNB) says is needed for good fetal health.

Hollis BW, Johnson D, Hulsey TC, Ebeling M, Wagner CL. Vitamin D supplementation during pregnancy: double-blind, randomized clinical trial of safety and effectiveness. J Bone Miner Res. 2011 Oct;26(10):2341-57. doi: 10.1002/jbmr.463

Surprise surprise, only the 4,000 IU/day pregnant women group even approached the minimal safety level of 20 ng/ml in their infants. Furthermore, the 2010 FNB recommendations of vitamin D in prenatal vitamins would have left 50% of the White women and 80% of the Black women with fetuses below 20 ng/ml.

However, Professor Hollis found something else, something potentially much more important. He found that the average fetus in the USA is starved for enough building blocks for his or her mother to make adequate activated vitamin D to ship to the baby; activated vitamin D that is probably used for microscopic organ development, such as in the brain.

Activated vitamin D in pregnancy is mysterious. It appears the mother makes it in her kidney (maybe some in her placenta) at levels up to 3 to 4 times normal (without maternal hypercalcemia) and ships it across to the fetus. This only happens if the mother has enough of this vital steroid hormone in her body to ship to the fetus and most mothers do not. If she can’t make it, she can’t ship it maximally, and the 38 fetal organs depending on activated vitamin D to fully develop must do the best they can do with inadequate amounts of this steroid. Of course, none of this applies to mothers who frequently sunbathe, or who take 5,000 IU/day while they are pregnant.

To quote Professor Hollis: “These findings suggest that the current vitamin D (requirements for pregnancy, currently 600 IU/day) issued in 2010 by the Food and Nutrition Board should be raised to 4,000 IU of vitamin D per day so that all women, regardless of race, can attain optimal nutritional and hormonal vitamin D status throughout pregnancy.”

The Vitamin D Council agrees and considers this an important study in support of why adults and pregnant women need at least 4,000 IU/day to elevate blood levels and improve fetal health and birth outcomes. Although there are no trials that support taking more, the Vitamin D Council believes 5,000 IU/day is equally safe and would be more effective at maintaining adequate fetal blood levels of vitamin D.

6 Responses to Optimal levels of vitamin D during pregnancy

  1. [email protected]

    From todays Scots paper, “the study had not been made public” … I am shocked, how much more proof do we need?

    Professor Ebers said: “I have to say I was shocked. The levels of vitamin D among pregnant women were breathtakingly low.”
    Last week, he questioned why the study had not been made public and demanded that Scottish ministers reveal the contents as a “matter of urgency.”

    But Professor Naveed Sattar, of the Institute of Cardiovascular and Medical Sciences at Glasgow University, however, is sceptical of such supplements.
    “Where is the evidence that giving vitamin D to pregnant women is beneficial to their offspring?


  2. rtfdc1

    I would put money on the esteemed Prof. Sattar being deficient in vitamin D.

  3. Chris

    My daughter delivered 7 months ago, she needed 7000iu per day to have a serum level of 125nmol/l, since delivering and while breast feeding she kept taking the same daily amount, and recently tested at 137 . She has also been giving the baby 4001u D drops….he tested at 120nmol/l.

  4. [email protected]

    For the past five years I have been recommending to all personally known pregnant women to take 10,000 IU of vitaminD3 and also supplement with high dose omega 3. one young lady send me an youtube of her baby laying on daddy’s chest on her abdomen and mother called baby’s name and literally she lifted her head and looked around to see where the voice came from and mother commented that she attributes this to her supplement intake. All the children of mothers who had taken adequate amount of D3 shows remarkable alertness, agility, observation, attention and are overall very calm and always in a playful mood. I have grand parents thanking me for my recommendation.
    Ashok Patel MD

  5. Margaret

    I wish I had been armed with this sort of data and information when I was pregnant with both of my children. I remember saying that I felt like the “life was getting sucked out of me” whenever I nursed them. I now believe that I was extremely low in Vitamin D. Both of my children have some brain issues of different varieties and it has taken sooo much of my time and so much health insurance to deal with their health issues. Our government would be incredibly foolish to not read and heed this article’s findings and advice.

  6. Margaret

    I would like to ‘thumbs up” rtfdc1’s comment above and double up on his bet.

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