Maternal vitamin D status, prolonged labor, and cesarean and instrumental delivery in an era with a low cesarean rate

Objective—To examine the association between maternal 25-hydroxyvitamin D (25(OH)D) and adverse labor and delivery outcomes. Study design—We measured serum 25(OH)D at ≤26 weeks gestation in a random subsample of vertex, singleton pregnancies in women who labored (n=2798) from the 12 site Collaborative Perinatal Project (1959–66). We used labor and delivery data to classify cases of adverse outcomes. Results—Twenty-four percent of women were vitamin D deficient (25(OH)D <30 nmol/L) and 4.5%, 3.3%, 1.9%, and 7.5% of women had prolonged stage 1 labor, prolonged stage 2 labor, primary cesarean delivery, or indicated instrumental delivery, respectively. After adjustment for prepregnancy BMI, race, and study site, 25(OH)D concentrations were not associated with risk of prolonged stage 1 or 2, cesarean delivery, or instrumental delivery. Conclusion—Maternal vitamin D status at ≤26 weeks was not associated with risk of prolonged labor or operative delivery in an era with a low cesarean rate. Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms Author for correspondence: Lisa M. Bodnar, University of Pittsburgh Graduate School of Public Health, A742 Crabtree Hall, 130 DeSoto St, Pittsburgh, PA, 15261, 412.624.9032 (voice), 412.624.7397 (fax), [email protected]. Reprint requests: Offprints will not be available. Conflict of Interest The authors report no conflicts of interest. HHS Public Access Author manuscript J Perinatol. Author manuscript; available in PMC 2015 July 01. Published in final edited form as: J Perinatol. 2015 January ; 35(1): 23–28. doi:10.1038/jp.2014.139. A uhor M anscript