Recurrent pregnancy loss – Low Vitamin D is a suspected risk factor – Sept 2018

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Vitamin D, autoimmunity and recurrent pregnancy loss: More than an association - Sept 2018

m J Reprod Immunol. 2018;e12991. First published: 19 June 2018 https://doi.org/10.1111/aji.12991
Kassem Sharif Yousra Sharif Abdulla Watad Yarden Yavne Benjamin Lichtbroun Nicola Luigi Bragazzi Howard Amital Yehuda Shoenfeld

PDF is available free at Sci-Hub  10.1111/aji.12991

Recurrent pregnancy loss (RPL) affects close to 1% of couples; however, the etiology is known in only about 50% of the cases. Recent studies show that autoimmune dysregulation is a probable cause of RPL, which in some cases may be overlooked. In order for a pregnancy to proceed to term, early modulation of immunologic response is required to induce tolerance to the semi‐allogenic fetus. Certain subsets of both the innate and adaptive immune responses play a role in the induction of fetomaternal tolerance. A relatively predominant T‐cell helper (Th) 2 and T regulatory (Treg) cell population seem to favor a better pregnancy outcome, whereas Th1 and Th17 cell populations appear to have an opposite effect. Lately, the role of vitamin D in the modulation of immune response was established. Vitamin D has been shown to promote a more favorable environment for pregnancy through various mechanisms, such as enhancement of the shift toward Th2 cells and regulation of immune cell differentiation and cytokine secretion.
Therefore, it seems that vitamin D deficiency sways the balance toward a worse outcome and may play a part in recurrent pregnancy loss. This review sheds light on the immunologic changes, which occur in early pregnancy and the regulatory role vitamin D has in the maintenance of this delicate balance.

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Recurrent pregnancy loss and vitamin D: A review of the literature - Nov 2018

American Journal of Reproductive Immunology https://doi.org/10.1111/aji.13022
Daniela Reis Gonçalves António Braga Jorge Braga António Marinho

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.