Low maternal serum 25-hydroxyvitamin D may explain the link between higher microbial prevalence in amniotic fluid during preterm labor

William B. Grant, Ph.D.
Sunlight, Nutrition, and Health Research Center (SUNARC)
P.O. Box 641603
San Francisco, CA 94164-1603, USA
www.sunarc.org
wbgrant@infionline.net

The report of higher microbial prevalence in amniotic fluid during preterm labor [DiGiulio et al., 2008] may be linked to low maternal serum 25-hydroxyvitamin D [25(OH)D] during pregnancy. One factor linked to preterm low birth weight is periodontal disease [Marakoglu et al., 2008]. Periodontal disease (PD) is the condition where bacteria form a biofilm on the teeth where their metabolic products including acids leech calcium from the teeth and alveolar bone, resulting in tooth attachment loss and, if left unchecked, tooth loss. There is good evidence that low serum 25(OH)D is a risk factor for periodontal disease [Dietrich et al., 2004, 2005]. A second risk factor for preterm birth is bacterial vaginosis [Hillier et al., 1995].

Additional support for a role of vitamin D in reducing the risk of periodontal disease is that vitamin D, through induction of human cathelicidin, LL-37, reduces the risk of bacterial and viral infections. “The human cathelicidin LL-37, for example, has modest direct antimicrobial activity under physiological conditions, but has been demonstrated to have potent antiendotoxin activity in animal models, as well as the ability to resolve certain bacterial infections.” [Mookherjee et al., 2007]. Reviews are found in Adams and Hewison [2008], Bikle [2008], and White [2008].

Thus, low maternal serum 25(OH)D likely explains the link found by DiGiulio et al. [2008]. It would be easy to test this possibility by simply measuring serum 25(OH)D for those having preterm births and compare the values to those giving normal births.

Disclosure
I receive funding from the UV Foundation (McLean, VA), the Vitamin D Society (Canada), and the European Sunlight Association (Brussels).

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