Effect of intrapartum vitamin D levels on labor pain

Vitamin D has widespread receptor distribution in the body, and therefore it has vital roles in numerous pathophysiological conditions. It also affects pain manifestation through its functions at various stages of the pain pathways. This study aimed to investigate the effects of intrapartum vitamin D levels on pain experienced by women during the first stage of labor.

A total of 127 term-nulliparous women at the early stage of labor were included in the study. Serum 25 (OH) vitamin D levels were measured at the beginning of labor to determine intrapartum vitamin D levels. Labor pain was assessed using the Visual Analog Scale at different stages of cervical dilation (VAS₀ , VAS₁ , VAS₂ ). Postpartum pain (VAS_pp ) and women's birth satisfaction score (BSS) were also evaluated during the early postpartum period.

There was a moderate negative correlation between vitamin D and VAS₀ and VAS₁ (r²  = 0.4, p = 0.000; r²  = -0.570, p = 0.000, respectively), and a weak negative correlation between vitamin D and VAS₂ (r²  = -0.373, p = 0.000). No significant correlation was found between vitamin D and BSS and length of labor (p = 0.127, p = 0.126, respectively).

In nulliparous women with low vitamin D levels, the first stage of labor and the early postpartum period may be more painful. To facilitate management of labor pain, during the antenatal period vitamin D levels should be monitored, and in cases where the levels are deficient, vitamin D supplementation should be started.