Merewood et al. Association between vitamin D deficiency and primary cesarean section. J Clin Endocrinol Metab. 2009 Mar;94(3):940-5. Epub 2008 Dec 23.
BACKGROUND: At the turn of the 20th century, women commonly died in childbirth due to rachitic pelvis. Although rickets virtually disappeared with the discovery of the hormone vitamin D, recent reports suggest vitamin D deficiency is widespread in industrialised nations. Poor muscular performance is an established symptom of vitamin D deficiency. The current U.S. cesarean birth rate is at an all-time high of 30.2%. The researchers' analyzed the relationship between maternal serum vD status, and prevalence of primary cesarean section.
METHODS: Between 2005 and 2007, we measured maternal and infant serum vD at birth and abstracted demographic and medical data from the maternal medical record at an urban teaching hospital (Boston, MA) with 2500 births per year. We enrolled 253 women, of whom 43 (17%) had a primary cesarean.
RESULTS: There was an inverse association with having a cesarean section and serum vD levels. They found that 28% of women with serum vD less than 37.5 nmol/liter had a cesarean section, compared with only 14% of women with vD 37.5nmol/liter or greater (P = 0.012). In an analysis controlling for race, age, education level, insurance status, and alcohol use, women with vD less than 37.5 nmol/liter were almost 4 times as likely to have a cesarean than women with vD 37.5 nmol/liter or greater (adjusted odds ratio 3.84; 95% confidence interval 1.71 to 8.62).
CONCLUSION: Vitamin D deficiency was associated with increased odds of primary cesarean section.
"A compelling story and ties in nicely with what we know about MS. The increased risk of MS in people born by C-section is an association and is not causal. Vitamin D deficiency may explain them both."