Recurrent pregnancy loss and vitamin D: A review of the literature

Abstract

Recurrent pregnancy loss (RPL) affects approximately 1%-2% of reproductive women. Auto- and cellular immune responses seem to be associated with RPL. Vitamin D (VD) has been shown to play a role in the modulation of the immune system. Effects of VD deficiency (VDD) in pregnancy have been associated with preeclampsia, gestational diabetes, fetal growth restriction, preterm labor, and sporadic spontaneous abortion (SA). We systematically reviewed articles that studied women with 2 or more SA and its association with VD. Eleven studies were included. Studies reported a high prevalence of VD insufficiency (VDI) or VDD in women with RPL and suggested that this could be associated with immunological dysregulation and consequently with RPL. Immunological benefits were reported in the peripheral blood of women with RPL after VD exposure. Thus, it is possible to speculate a beneficial role for VD supplementation in RPL. It seems that there are not differences in the vitamin D receptor (VDR) and CYP27B1 expression in endometrium of women with RPL but, in villous and decidual tissues, RPL women seem to have a decreased expression of VDR and, perhaps, a decreased expression of CYP27B1. Further randomized controlled studies are required to investigate the association between VDD or VDI and RPL.

A novel update on vitamin D in recurrent pregnancy loss (Review)

“…Excessive inflammatory response and lower levels of vitamin D are found in women with RPL (67). As observed in a previous study, patients with VDD showed an notable higher percentage of TNF-α-secreting Th cells relative to individuals with normal vitamin D levels (35.1±10.2 vs. 28.3±4.8%; P<0.05), whereas the difference between vitamin D insufficient group (VDI) and VDN was negligible (2).…”

Safety and efficacy of supplements in pregnancy

“… 71 Recurrent pregnancy loss affects 1%–2% of reproductive women and studies show an association with vitamin D deficiency. 72 Vitamin D level, therefore, may be an important clinical consideration, particularly as recurrent pregnancy loss is often unexplained.…”

The Role of Vitamin D in Fertility and during Pregnancy and Lactation: A Review of Clinical Data

“…Vitamin D RCTs specifically designed to assess outcomes of ART are, however, still missing. Interestingly, one meta-analysis documented that early spontaneous pregnancy loss was significantly increased in women with serum 25(OH)D concentrations below 50 nmol/L compared to those with higher 25(OH)D levels (relative risk (RR): 2.24; 95% CI: 1.15 to 4.37) [ 54 , 55 , 56 ]. In line with this, a study in 1191 women with previous pregnancy losses showed that women with serum 25(OH)D concentrations ≥75 nmol/L preconception were more likely to achieve clinical pregnancy (adjusted RR: 1.10; 95% CI: 1.01 to 1.20) and livebirth (RR: 1.15; 95% CI: 1.02 to 1.19) compared to those with lower serum 25(OH)D concentrations [ 57 , 58 ].…”