Vitamin D and Pregnancy

[facetguy]

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It appears that pregnant women need considerably more vitamin D than previously thought. http://www.sciencedaily.com/releases/2010/05/100501013417.htm

Does anyone here recommend vitamin D at these levels to their pregnant patients, or does anyone routinely test for blood levels of vitamin D?

 

[Eta Carinae]

great topic.

I was about to question the validity of the source and the study, but apparently it was presented at the pediatric Academics Society in Vancouver, BC and was authored by a faculty member at the Medical University of South Carolina.

Their n was also pretty substantial, 494 for an OB study.

The article reports a decrease in

• preterm labor
• preterm births, and
• infection 😕

The infection part makes me really suspicious that they did not control for confounders between the two groups. I cannot think of a mechanism for vitD boosting the immunologic response to infection.

What do you guys do? 400? 1200? 4000 IU?

 

[facetguy]

great topic.

I was about to question the validity of the source and the study, but apparently it was presented at the pediatric Academics Society in Vancouver, BC and was authored by a faculty member at the Medical University of South Carolina.

Their n was also pretty substantial, 494 for an OB study.

The article reports a decrease in

• preterm labor
• preterm births, and
• infection 😕

The infection part makes me really suspicious that they did not control for confounders between the two groups. I cannot think of a mechanism for vitD boosting the immunologic response to infection.

What do you guys do? 400? 1200? 4000 IU?

Immune modulation is one of vitamin D's strongest attributes.

 

[Eta Carinae]

Immune modulation is one of vitamin D's strongest attributes.

Oh yeah, thanks for the reminder about Vit D's immunologic role.

By all indications though, Vit D's immune modulating potential is marginal at best. I certainly hesitate to describe it as one of it's strongest attributes. It also has a role in the potentiation of proinflammatory responses in the host, so one can only hope that the immunomodulatory effects outweigh its proinflammatory effects.

furthermore, the description of an actual mechanism for a theoretical decrease in placental infection is a relatively new area of study and I cannot find a definitive mechanistic outline.

Until a satisfactory description of confounding variable control is outlined, I'm not convinced.

 

[facetguy]

Oh yeah, thanks for the reminder about Vit D's immunologic role.

By all indications though, Vit D's immune modulating potential is marginal at best. I certainly hesitate to describe it as one of it's strongest attributes. It also has a role in the potentiation of proinflammatory responses in the host, so one can only hope that the immunomodulatory effects outweigh its proinflammatory effects.

furthermore, the description of an actual mechanism for a theoretical decrease in placental infection is a relatively new area of study and I cannot find a definitive mechanistic outline.

Until a satisfactory description of confounding variable control is outlined, I'm not convinced.

Immune modulation may not be vitamin D's strongest attribute (I think we can say that its role in calcium/bone metabolism is, or is at least its best understood role), but it is an area of current investigation. But you had asked why infection was on the list of beneficial effects, so it seemed appropriate to mention this.

As to proinflammatory effects, there is at least as much literature suggesting an anti-inflammatory role (I'd say considerably more). It's an unsettled issue for sure, and we'll probably find that the 'modulation' function will turn out to be at play ("boosts" immunity in some situations, "dampens" immunity in others--we are seeing that already in the auto-immune literature).

Bottom line: there is no reason to allow patients, including pregnant ones and neonates, to be vitamin D deficient, and there is plenty of literature showing they are. Give them what they need to at least fall into the low-normal range. Over time, we'll discover more about optimal ranges.

 

[facetguy]

From May's Am J Obstet Gynecol: http://www.ncbi.nlm.nih.gov/pubmed/20060512

Large numbers of pregnant and nonpregnant women have low vitamin D, and prenatals often don't provide enough D. In this study, 69% of pregnant and 78% of nonpregnant women were below the minimum-normal of 30 ng/mL (75 nmol/L). New data suggests pregnant women may need more like 4000 IU/day.