Vitamin D and the risk of dystocia: A case-control study

Abstract

Background Dystocia is one of the most common causes of cesarean section in nulliparous women. Studies have described the presence of vitamin D receptors in the myometrium, but it is still unclear whether vitamin D affects the contractility of the smooth muscles. We therefore aimed to determine the association between the vitamin D serum level at labor and the risk of dystocia. Method We conducted a case-control study between January 2012 and June 2017. Cases were primiparous women, with spontaneous onset of labor, who gave birth by cesarean section due to dystocia. Controls were primiparous women with a spontaneous vaginal delivery. We included 60 women (30 cases and 30 controls) in the analysis. The differences between cases and controls were assessed using chi-squared test for categorical variables and twosample t-test or unequal t-test for continuous variables, as appropriate, after evaluation of whether they followed the normal distributions. Results The mean serum 25-hydroxyvitamin D concentrations were 53.1nmol/l (95%CI; 45.2 to 60.9) among cases and 69.9nmol/l (95%CI; 57.5 to 82.4) among controls (P = 0.02). The mean plasma parathyroid hormone levels were 2.25 pmol/l and 2.38, respectively (P = 0.57). Even though 78% of all women reported taking a minimum of 10μg/day of vitamin D throughout pregnancy, 43% had vitamin D insufficiency, defined as serum 25-hydroxyvitamin D levels below 50nmol/l. Conclusions In a Danish group of women having a cesarean section due to dystocia, we found decreased vitamin D levels.

Mode of delivery and maternal vitamin D deficiency: an optimized intelligent Bayesian network algorithm analysis of a stratified randomized controlled field trial

“…Another cross-sectional study on 200 Indian pregnant women with singleton pregnancies showed a higher prevalence of hypovitaminosis D among mothers who underwent cesarean delivery compared to those who delivered vaginally (92% of women with vitamin D deficiency and 6% with insufficiency versus 85.6% with deficiency and 10.8% with insufficiency) 14 . A case–control study of 60 Danish women demonstrated a significant association between serum 25(OH)D levels and an increased risk of emergency cesarean section due to dystocia, highlighting the importance of vitamin D in the preparation of the uterus muscles and smooth muscle contractility during normal vaginal delivery 44 . Similarly, another study on 2,251 low-income pregnancies demonstrated that after adjusting for energy intake, other nutrients, and other potentially confounding variables, women with vitamin D deficiency had a two-fold increased risk of cesarean delivery due to prolonged labor compared to those with sufficient serum concentrations 45 .…”

“…Adequate levels of serum calcium are necessary for initiating labor, and vitamin D deficiency may negatively impact both skeletal muscle and smooth muscle strength, leading to specific etiologies of cesarean delivery such as CPD or failure to progress 12 . Vitamin D may affect myometrial contractility via two pathways: involving the intracellular vitamin D receptor and changes in the calcium metabolism 44 . Invitro studies have demonstrated that vitamin D regulates contractile proteins in myometrial cells 48 .…”

The association between maternal vitamin D deficiency and postpartum hemorrhage and uterine atony

“…Vitamin D deficiency was associated with muscle mass strength and one previous report has shown that vitamin D plays a role in the regulation of contractility in the myometrium 17 . In some previous published research vitamin D deficiency has been shown to increase the risk of CS due to dystocia based on its effect on striated muscle cells as well as possible effect on the myometrium 18–21 . Vitamin D supplementation during pregnancy has previously been suggested to prevent PPH 21–23 .…”

“… 17 In some previous published research vitamin D deficiency has been shown to increase the risk of CS due to dystocia based on its effect on striated muscle cells as well as possible effect on the myometrium. 18 , 19 , 20 , 21 Vitamin D supplementation during pregnancy has previously been suggested to prevent PPH. 21 , 22 , 23 As reduced myometrial contraction also causes atonic PPH, the matter of vitamin D deficiency and PPH should be further evaluated.…”

Does antenatal cholecalciferol supplementation affect the mode or timing of delivery? Post hoc analyses of the MAVIDOS randomized controlled trial

“…28,29 Furthermore, a recent meta-analysis of observational studies suggested that the timing of vitamin D deficiency may be important to the risk of preterm birth, with only deficiency in the second, and not the third, trimester being of potential importance to this outcome. 30 Several recent observational studies have also shown lower maternal 25(OH)D levels in those requiring Caesarean section compared with vaginal delivery, [31][32][33][34] but observational studies can be confounded by factors that affect both maternal 25(OH)D and risk of needing an operative delivery, such as maternal obesity, gestational weight gain and ethnicity. 35 Christoph et al found vitamin D deficiency reduced the incidence of PPH in an observational study.…”